Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 50, 1918

Transactions
of the
New Zealand Institute
,
1917.

Art. I:—The Prothallus and Young Plant of Tmesipteris.

[Received by Editors, 31st December, 1917; issued separately, 24th May, 1918.]

Plates IIII.

It has been mainly, perhaps, owing to the fact that the various members of the Psilotaceae are confined to tropical and subtropical regions, and to the temperate countries of the Southern Hemisphere, that our knowledge of the gametophyte and of the embryogeny of the sporophyte of this interesting group of plants has increased so slowly. This order has been the last to yield information with regard to the early stages in the life-history of its members, and so to furnish evidence which may help us to form reasonable theories concerning its genetic relationships. The genus Tmesipteris, for example, is confined to Australia, New Zealand, and certain Pacific islands, and hence has remained for the most part beyond the reach of European and American botanists.

With regard to not a few of the chief pteridophytic groups, not only has the number of those who have searched for the prothallus been limited, but the search itself has been rendered difficult on account of the fact that the gametophyte is often subterranean, and also that although the adult plants are not as a rule rare in their occurrence, yet their abundance in any particular locality is often due largely to their powers of vegetative reproduction, for the germination of the spores seems only to take place in localities where the conditions are peculiarly favourable, and where also the prothallus and young plant will remain quite undisturbed during the protracted period of their development. However, it seems to be evident from the writings of most of those who have given an account of the details of their search for pteridophytic prothalli that when once one can learn from experience in the field to recognize the localities favourable to the development of the particular kind of prothallus searched for there is no obstacle other than the necessity for patience in dissecting to hinder its being collected in comparative abundance.*

There is no doubt that the wet temperate climate of that part of New Zealand subject to the excessive western rainfall is especially favourable to pteridophytic growth and to the sexual reproduction of the plants. In the present paper I propose to give an account of my search for and discovery of the prothalli and young plants of Tmesipteris in the neighbourhood of Hokitika, in the Province of Westland, New Zealand, and to describe the form, structure, and development of the prothallus and sexual organs and of the young plant, and also to trace some of the early stages in the development of the embryo. Two writers have published certain results obtained by them in their search for the gametophyte of the Psilotaceae. Lang (1904) has given a description of a single prothallus which he has provisionally referred to Psilotum. This prothallus is certainly a puzzle, for on the one hand the finding-place strongly suggests that it belongs to Psilotum, but on the other its form and structure differ very widely from what I propose to describe for Tmesipteris, and from what Professor A. A. Lawson, of Sydney University, has already described. Lawson (1917A) gives a preliminary account of the prothallus of Tmesipteris based upon several specimens obtained by him from different localities in eastern Australia. This account was published early in 1917, but came into my hands only at the end of the year, when my own paper was almost completed. No reference to it, therefore, will be found in the body of the present paper, but in the concluding section I have compared in detail my own results with his, and noted our points of agreement or otherwise. There is a considerable literature dealing with the anatomy and morphology of the adult plant in the Psilotaceae. The more recent of those writings, such as those of Scott (1909), Bower (1908), Seward (1910), Thomas (1902), Boodle (1904), Ford (1904), and Sykes (1908), have brought together a weighty body of evidence for relating the Psilotaceae with the fossil Sphenophyllales. In my comparative remarks I have endeavoured to consider the results obtained from the study of the prothallus and young plant of Tmesipteris with regard to the systematic position to be assigned to Tmesipteris and Psilotum.

As on other occasions, I desire to acknowledge the special debt of gratitude I am under to Dr. L. Cockayne, F.R.S., for his constant encouragement and advice, and also to Professor C. Chilton, M.A., D.Sc., for his kindness in giving me free access to the Botanical Laboratory at Canterbury College.

[Footnote] * The following may be cited in this connection: H. Bruchmann, Uber die Prothallien und die Keimpflanzen mehrerer europäischer Lycopodien, pp. 4 and 5, 1898; D. H. Campbell, The Eusporangiatae (the adult gametophyte of Ophioglossum moluccanum, and O. pendulum), pp. 11 and 13, 1911; M. Treub, “Some Words on the Life-history of Lycopods” (tropical species), Ann. of Bot., vol. 1, pp. 119–23, 1887; J. E. Holloway, “Studies in the New Zealand Species of the Genus Lycopdium, Part I,” Trans. N.Z. Inst., vol. 48, pp. 259–63, 1916. In the last-mentioned paper I described the discovery of three species of Lycopodium prothalli of the L. cernuum type, one epiphytic species of the L. Phlegmaria type, and three subterranean species of the L. complanatum and L. clavatum types, the three latter being found in abundance. Since writing this paper I have found the prothalli of the three epiphytio varieties of Lycopodium which occur in New Zealand, in the case of two of them in great abundance, and have also continued to come across sporeling plants and prothalli of the three subterranean species in many different localities, and in large numbers.

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Tmesipteris tannensis (lanceolata) growing in humus along trunk of fallen tree, Stewart Island forest. (Photograph.)

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Occurrence and Habit.

Tmesipteris occurs commonly throughout New Zealand as an epiphyte on the stems of tree-ferns and other forest-trees. The much-branched brown rhizome penetrates through the mass of aerial rootlets which densely clothes the stem of the tree-fern, and especially is to be found underneath the decurrent stipites of its fronds. Certain of the rhizome-branches turn upwards, and emerge as green aerial shoots, bearing scattered scale leaves below and above the full-sized leaves of characteristic form and the sporophylls.

There is a certain amount of variation noticeable in the habit and general form of the plant, which is probably to be put in connection with the nature of the surface on which it grows. However, it must be noted that some writers have recognized distinct varieties. For example, when growing on certain species of the tree-fern Cyathea the whole plant is generally somewhat stunted in size, the rhizome being more scantily branched and the aerial shoots short and semi-erect. In these cases the surface of the tree-fern stem consists solely of the mat of black brittle aerial rootlets, the stipites of the fronds not reaching down the stem much below its crown, and consequently there being only the dense tough mat, of greater or lesser thickness, of the interlaced rootlets in which the Tmesipteris plants can grow. My experience has been the same probably as that of others who have tried to dissect out the plants from such intractable material. It is almost impossible to get the plant with all its various branchlets complete, and one gives up in despair the search for the young plants or for the prothallus.

In those paits of New Zealand, however, especially in the botanical districts, as defined by L. Cockayne,* which lie for the most part west of the Southern Alps, together with that ecologist's South Otago and Stewart Districts, where the average rainfall is very heavy, there is an extremely rich growth of Pteridophytes, and Tmesipteris occurs abundantly on the tree-fern Dicksonia squarrosa and on moss- or humus-covered forest-trees, and also in the heaps of humus which lie on the ground at the bases of the trees. Here the size and habit of the plant are markedly different from those described above. The penetrating rhizomes may be as much as 2 ft. or 3 ft., or even more, in total length, and are for the most part extensively branched; also, it is an easier matter to dissect out a plant entire from such a substratum. The aerial branches arising from a single plant are fairly numerous, and droop down 2 ft., 3 ft., and 4 ft. in length, the branches of groups of plants hanging like a fringe from some tree-branch or fallen tree-stem. In Plate I is shown a single plant with a much-branched rhizome and three aerial stems, the latter showing fertile regions.

I have found in the neighbourhood of Hokitika, Westland, in the low-lying forest which borders the sea-front, both young and mature plants of Tmesipteris growing on the stems of Dicksonia squarrosa in great abundance. On this particular tree-fern the frond-stipites run down the stem for some distance before they enter its surface, and hence in young individuals the greater part of the stem, and in older plants the upper portion, is covered with the adhering bases of the fronds. The young plants of Tmesipteris occur both immediately underlying the stipites and in the ridges of aerial rootlets which project outwards between them. During the month of September, 1917, I obtained several lengths of tree-

[Footnote] * Trans. N.Z. Inst. vol. 49, p. 65, 1917.

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fern stems which showed the presence of abundant young plants of Tmesipteris, and took them home for dissection. Between twenty and thirty prothalli were discovered on this occasion in all stages of development (except, of course, the very youngest), some of these prothalli bearing young plants in various stages of growth. During the following two months many other prothalli were obtained in the same way, the total number to date being between sixty and seventy, as well as many isolated prothallial plantlets, some of the latter being complete and others broken in process of dissection.

By reason of their brown colour and large size, the prothalli and the rhizomes of the young plants are clearly to be seen amidst the tangle of black aerial tree-fern rootlets. There is not much humus present, but the rhizoids of the prothalli and plantlets are closely intermixed with ramenta from the tree-fern. Prothalli and plantlets also of Lycopodium Billardieri var. gracile were found in abundance on these tree-ferns, and also the prothalli of various ferns and several liverworts. The spores of Tmesipteris germinate best on those parts of the tree-fern stems where the surface, owing to the presence of the frond-stipites, is more loose and open. The young plants, once established, will develop, and their rhizomes ramify in all directions, even after the bases of the fronds have completely fallen away and their places have been filled up by the mat of aerial rootlets; but the younger plantlets will only be found higher up the stem. It was noticed that in the groves of Dicksonia squarrosa in this particular locality many. young tree-ferns of from 6 ft. to 8 ft. in height bore young developing plantlets of Tmesipteris, but that it was only on still taller stems that the mature plants were to be seen, whilst from those of 15 ft. or more in height the plants had generally disappeared altogether from the lower portions of the stem and were only to be found on the upper half. It would seem that Tmesipteris prefers a fairly loose substratum both for the germination of its spores and also for the full development of the plants.

That this is so becomes apparent when one observes the conditions under which it flourishes on Stewart Island and on those parts of the mainland (e.g., Bluff Hill) which face Stewart Island across Foveaux Strait. In these localities Tmesipteris occurs very commonly in the masses of loose humus which are gathered at the bases of forest-trees and tree-ferns, and there the plant often reaches a most luxuriant development. Also, on such large branches and tree-trunks throughout the forest as are covered with humus, and especially on those which lie more or less horizontal, there is frequently a rich growth of the plant. In January, 1915, I made a visit to Stewart Island for the purpose of searching for the young plants and prothalli of Tmesipteris. This botanical district is well known to be exceptionally favourable for the growth of epiphytic ferns and lycopods, on account of its wet climate. There is one locality especially, bordering the shore of Preservation Inlet, near the upper reaches of its south-west arm, where there is a very characteristic and interesting type of forest. This has been described by L. Cockayne in his Report on a Botanical Survey of Stewart Island (Government Printer, Wellington, 1909). Cockayne speaks of this type of forest as “the Yellow-pine (Dacrydium intermedium) Association.” This particular association is confined to wet ground, and the low forest consists mainly of the small pine which gives its name to the association, and of other conifers, as, for example, Dacrydium biforme, Podocarpus Hallii, and certain other species belonging to these two genera; while the floor of the forest is covered with curious

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large globular cushions of mosses and liverworts (e.g., Dicranoloma Billardieri and species of Plagiochila) from 1 ft. to 2 ft. or more in diameter, and with three species of Lycopodium (L. volubile, L. scariosum, and L. varium) growing in wonderful luxuriance. Lycopodium varium here grows in great clumps, which are as much as 6–8 ft. across. Tmesipteris and filmy ferns are also in great abundance—in fact, the general appearance of the vegetation is suggestive of a past age when Gymnosperms and Pteridophytes were dominant rather than Phanerogams. During my visit to Stewart Island I arranged an expedition to spend a few days in this locality, but owing to heavy rains and floods the party was isolated on the sea-coast and nearly met with disaster. However, on the last day I reached the spot, and during an hour's search succeeded in finding several young prothallial plantlets of Tmesipteris growing in thick loose humus on a fallen tree-trunk. There is no doubt that with longer time at his disposal a searcher would find the place a most favourable one for the discovery of both the young plants and the prothalli.

It was not till the spring of 1917 that the further discovery was made, in the neighbourhood of Hokitika, of both plantlets and prothalli of Tmesipteris, as recorded above. In the dissection of these specimens from the mass of aerial rootlets on the stems of the tree-ferns a certain amount of patience and care had to be used, for these rootlets are exceedingly tough and are closely intermatted, and both the prothalli and rhizomes of Tmesipteris are very brittle and easily broken. However, by pulling away the stipites of the tree-fern fronds and carefully tearing apart the mass of aerial rootlets the golden-yellow rhizomes and the brown prothalli were easily to be seen (by reason both of their characteristic colour and of their comparatively large size), and, the black aerial rootlets being cut away with dissecting scissors, they were readily obtained.

General Form and Structure of the Prothallus.

The prothallus-body is cylindrical in form, being radially constructed. It is brown in colour, and is covered with numerous long golden-yellow rhizoids. It never seems to reach the light, and is quite destitute of chlorophyll. The largest specimens found are shown in figs. 5, 6, and 8, being 18 mm. and 13 mm. respectively in total length, and the smallest in figs. 11 and 12, these being from 1 mm. to 2mm. long. In its unbranched form the prothallus is carrot-shaped, tapering down gradually from a fairly thick head and upper region towards the basal first-formed end, which culminates in a more or less long-drawn-out point (figs. 1, 2, and 11). The first-formed basal region does not show such a marked primary tubercle as is so well known in the case of the prothalli of Lycopodium cernuum or in those of Ophioglossum and Helminthostachys, but there is commonly a succession of gentle swellings from, the original point of growth upwards by which the prothallus grows in girth (figs. 1, 2, 11, and 13). The actual head is generally the stoutest region (figs. 12, 13, & c.), being sometimes curiously swollen, and the growing apex is bluntly rounded.

Sooner or later the head of the prothallus forks dichotomously, and one of the branches so formed may later fork again. In some cases the first branching is postponed till after the prothallus has attained a length of as much as 8–10 mm. (figs. 1, 2), and the result is the carrot form; more often, however, the first forking takes place comparatively early (fig. 6), and many adult prothalli were found in which one of these

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branches had developed into the main prothallus-body, whilst the other had either broken away or persisted towards the base of the first in a state of arrested growth (figs. 4, 5, 6). The forking generally seems to result at first in two equal apices of growth (figs. 1, 2), and hence may be termed dichotomous, and, except in the case of the first branching as just described, which takes place when the prothallus is still comparatively small, the resultant branches become more or less equally developed (figs. 2 and 5). Hance in most adult prothalli found the original simple carrot shape form had been lost, and the prothallus had become more irregular in appearance, such as is generally the case with epiphytic prothalli. Thus in this respect the prothalli of Tmesipteris can be compared with those of the epiphytic species of Lycopodium and Ophioglossum. In a few instances, moreover, such as those illustrated in figs. 6 and 66, a still greater irregularity of form had been brought about through the branching not taking place dichotomously. In the former of these two prothalli the forking seems to have been trichotomous. Still another irregularity in the form of adult prothalli is brought about by the equal development of both daughter branches at the first forking of the prothallus, not, as is usually the case, at an angle to one another, but in directions diametrically opposite (fig. 7). This is still more pronounced in the case of the large prothallus shown in fig. 8, in which one of the branches resulting from the first forking had forked again, the two branches of this second forking proceeding to develop in opposite directions to one another in the sme straight line. Thus the branched form of the adult prothallus is attained normally by the dichotomous forking of the apex, but I observed also a few instances in which short undeveloped branches had arisen apparently laterally. However, even in the most irregularly shaped adult individuals the manner of growth can always be easily traced, for even if the original long-drawn-out point be not preserved, yet the oldest region can always be distinguished from the rest of the prothallus by its darker brown or even almost black colour.

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Fig. 1.—Complete prothallus, carrot form, bearing young plant, and showing original end intact. × 10.
Fig. 1A.—Original end of prothallus shown in fig, 1. × 24.

On some of the prothalli a large cup-shaped prominence with an obviously lacerated rim was to be seen (figs. 4 and 73). This is where a young plantlet had been broken away, the cup-shaped prominence having been formed by the localized outward growth of the prothallial tissues around the embryo and their final rupture by the developing plantlet. Such a point of attachment of the plant to its parent prothallus

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may be seen sometimes in the lower regions of the latter (fig. 5), indicating that the growth of the prothallus is by no means arrested by the development on it of a plant, but may go on after the latter has attained. a considerable size or has even become detached from the prothallus.

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Fig. 2.—Complete prothallus, carrot form, commencing to fork, bearing young plant. × 9.
Fig. 3.—Prothallus, carrot form, original end broken off, showing swollen head. × 12.
Fig. 4.—Prothallus, branched, one branch broken off, shows original end intact, also point of attachment of young plant. × 12.
Fig. 4A.—Original end of prothallus shown in fig. 4. × 36.

When first seen amongst the tangle of black aerial rootlets of the treefern stem the prothalli may easily be mistaken for broken portions of the rhizome of young plants or for very young complete isolated plantlets, and vice versa. Both the prothalli and the rhizomes are brown in colour, and both are covered fairly thickly with the long yellow-brown rhizoids or with the characteristic small brown circles formed by the persisting bases of broken-off rhizoids. The similarity holds also with regard to their growing apices, which are always somewhat swollen and are clear and whitish in appearance and show rhizoids only in their earlier stages of development. Each object dissected out has generally to be separately cleaned and examined under a low power of the microscope before its nature can be definitely determined. This is especially so in the case of the branched prothalli, whereas the carrot — shaped individuals are more easily recognized. However, generally speaking, the colour of the

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prothallus is more opaquely brown than that of the rhizome, the latter appearing a clearer golden brown, with its surface cells outlined with great distinctness, this difference in appearance being due possibly to the denser fungal element in the interior tissues of the prothallus. The older basal regions of the prothalli are often darkly brown in colour or even blackish, owing not so much to any withering-away of the tissues as to the presence of the mycorhiza in this region in the cells immediately underlying the epidermis, and, in the oldest regions of all, in the epidermal cells also, as well as in those more centrally situated.

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Fig. 5.—Complete branched prothallus of large size, bearing young plant which shows both rhizome and serial stem. × 3.

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Fig. 6.—Complete branched prothallus of large size, one main branch showing further irregular branching. × 10

The prothallus in transverse section is round in outline (figs. 16 and 17), this being so throughout its length, so that its construction is consistently radial. Its growth in length is referable to the activity of a single cell (figs. 20 and 21), such as is the case also with the cylindrical prothalli of the Ophioglossaceae. A transverse section through the main

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body of the prothallus shows its tissues to be composed of cells of uniform size and shape, there being no differentiation of central long conducting cells or of fungal zones such as are so well known in most of the types of Lycopodium prothalli. The dense fungal coils occupy uniformly practically all the cells in the central region, the epidermis and a zone three or four cells in width immediately underlying it alone being free from these coils. In the limbs of the larger prothalli this subepidermal layer sometimes contains much starch. Moreover, meristematic activity sometimes shows itself in these cells (fig. 19), though whether in connection with the storage of starch or with the development of the sexual organs is not quite clear. The mycorhiza extends uniformly right up through the length of the prothallus to close behind the actual apex, keeping pace with the forward growth of the latter. A series of transverse sections behind a growing apex shows that at its uppermost limit the mycorhiza occupies only a narrow central core of cells, which gradually tapers off upwards, and that in these cells the hyphae are more scantily developed. The fungal hyphae in these growing regions of the prothallus are wholly absent from the cells which surround the central core, this fact showing that when once the mycorhiza has entered the prothallus in its earliest stages of development no further infection is needed, but that the fungus extends upwards in a uniform manner, keeping pace with the growth of the prothallus. The clear white colour of the actual apex is, of course, due to the absence of the fungus from its cells. In the older parts of the prothallus hyphae can often be distinguished penetrating through the length of rhizoids and across the outer layers of cortical cells, but it is probable (as is also considered to be the case in other pteridophytic prothalli which are infected with a mycorhiza) that this signifies no organic connection between the fungal

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Fig. 7.—Complete branched prothallus, in which the branches are not inclined to each other at angle but in opposite directions. × 10.
Fig. 8.—Branched prothallus, one branch broken; the other has branched again in the manner described for fig. 7. × 5.

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hyphae within the prothallus and those in the surrounding humus. A great outward growth of hyphae was noticed from the surface of teased-up portions of young rhizomes which had been kept for some days in water in a watch-glass, and many of the threads showed what seemed to be single round spores at regular distances along their length. At its uppermost limit the hyphae of the mycorhiza in the interior cells of the prothallus are scantily developed, but farther back the coils become more dense. Throughout the greater part of the prothallus the fungal contents of each cell show as a dense globular mass,in which the identity of the hyphal threads can no longer be traced. These globular contents of the cells present a very characteristic feature both in the prothallus and young rhizome. (See Plate II.)

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Fig. 9.—Old withered prothallus, carrot form, attached to plantlet which is broken above and below. × 3.
Fig. 10.—Old withered branched prothallus, attached to plantlet from which aerial stem is broken off. × 2.
Fig. 11.—Very young complete prothallus, showing original end intact and antheridia on its head. ×45.

Not a few well-grown prothalli showed the original point of growth almost intact, and the remains of the first-formed filament, which arises, presumably, immediately from the spore, could be very clearly seen (figs. 1A, 4A, 11, 12, and 13). In two instances—namely, the very young prothallus shown in fig. 11 and the much older one in fig. 1A — there was present at the extremity of the basal end a short filament of cells, two or three in length, which in the former case was seen to be incomplete,

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but in the latter was apparently quite complete. The prothallus shown in fig. 4A tapered off at the basal end to a single cell, which showed no sign of original farther extension such as would compare with the longer filament in figs. 1A and 11. But the single cell in which the basal point of most of the youngest prothalli found by me terminated did give evidence of having had a farther cellular extension broken away from it. In all these prothalli the terminal basal cells, whether single or in the form of a short linear filament, all contained the same dense masses of the fungal element which are present in the other parts of the prothallus. Thus it would seem that the fungus enters the prothallus immediately the spore begins to germinate, unless perhaps we take it that it spreads downwards into the filament subsequent to the infection of the prothallus through the first-formed rhizoids. Probably the delicate original basal filament owes its preservation to the fact of the presence in its cells of these fungal masses, the collapse of the cells being thus prevented. At any rate, the preservation of the actual original point of the prothallus of Tmesipteris in so many individuals, some of which were well grown, is rather remarkable. It would seem, then, though it must be stated that the remains of the originating spore itself have not been seen, that on germination the spore gives rise to a short linear filament of cells, and that this, after from one to three or more single cells have been cut off, proceeds to the formation of a cell-mass. This basal primary tubercle is well preserved in the prothalli shown in figs. 1, 2, 4, 11, 12, and 13, and it will be seen that in most cases it shows no great development. The further stages of growth of the prothallus can be clearly seen from a comparison of the young and the older individuals shown in these figures. The prothallus grows in a succession of gentle swellings, each a little bigger than the last, the increased cell-multiplication which these swellings indicate being due probably to the accumulation of food material at the apex, consequent on the activity of the mycorhiza. In fig. 14 is shown one of the limbs of the large prothallus illustrated in fig. 6; serial sections through this limb showed that the cells of the apical region were packed with starch. Thus, as the prothallus grows, its apex becomes more and more bulky, so that the whole prothallus-body acquires the carrot form, until at length, owing probably to the stimulation set up by the presence of abundant

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Fig. 12. — Very young complete prothallus, showing papillose-like outgrowth of epidermal cells. Antheridia on head. × 45.

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food contents in its cells, the head of the prothallus forks and the carrot form gives place to the branched form characteristic of the full-grown individuals.

The Distribution of the Sexual Organs.

There is no differentiation of the prothallus into vegetative and reproductive regions, such as is usual, for example, in the terrestrial forms of Lycopodium prothalli. The sexual organs are distributed over the surface of the whole prothallus-body in large numbers, and often in groups. A transverse section of the limb of a prothallus will often show either antheridia or archegonia distributed more or less all around the surface (figs. 16 and 17). The sexual organs are for the most part more intermingled than is the case in the branched prothalli of the epiphytic lycopodiums, and correspond in this particular rather to the prothallus of Ophioglossum (Campbell, 1911, p. 10).

The young developing sexual organs are to be found immediately behind the growing apex of the prothallus, but also, as is known to be the case in Ophioglossum (ibid., p. 29), they frequently arise much farther back from it amongst old organs. As a rule, however, both the antheridia and the archegonia arise immediately behind the growing apices in acropetal succession. In nearly every prothallus I noticed developing antheridia on the growing branches, in some cases the youngest being fairly close behind the actual apex, whilst in others (where possibly the growth in length of the branch was taking place more rapidly) at a greater distance back from it. In only a very few out of the large number of prothalli found by me were groups of young archegonia to be seen close behind the apex. This fact, however, is probably due to chance only, for archegonia always occur in large numbers on the main prothallus-body, though the tendency to grouping is more to be remarked in the distribution of the archegonia than of the antheridia. It may possibly be that the archegonia arise in an irregular manner on older parts of the prothallus more frequently than do the antheridia. In several instances of adult prothalli (figs. 1, 2, and 3) where growth had slackened, old archegonia were present in fairly large numbers close behind the apex.

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Fig. 13.—Young complete prothallus, showing swollen head, sexual organs, and original end. × 16.
Fig. 13a.—Original end of prothallus shown in fig. 13. × 30.

In the very young prothalli shown in figs. 11 and 12 it will be seen that the sexual organs begin to develop comparatively early, and that it is the antheridia that are first formed. The basal regions of older prothalli also generally show the presence of old antheridia. In surface appearance the young developing antheridia are seen as colourless hemispherical proturberances (figs. 6, 12, 13, & c.). This is generally one of the most

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marked features of the growing head of the prothallus. Developing antheridia in surface view are shown in fig. 14. There is a single opercular cell at the apex of the protuberance, whose walls early become brown in colour, thus defining the cell very clearly. This browning soon extends to the walls and contents of all the outer cells on the free portion of the antheridium. In the ripe antheridium the interior mass of spermatocytes can clearly be seen in surface view. The antheridium is emptied through the breaking-down of the opercular cell, the aperture thus formed becoming enlarged in still older individuals by the breaking-away also of those cells which adjoin the opercular cell. Thus the characteristic appearance of old antheridia all over the main prothallus-body is that of brown cup-shaped structures projecting from the prothallus-surface (fig. 14, & c.).

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Fig. 14.—One of the large heads of prothallus shown in fig. 6, with antheridia in various views. × 52.
Fig. 15.—Small head of a prothallus, showing archegonia in various stages of development. × 66.

The young archegonium is first visible in surface view from the division into four of its outer cell and their arrangement quadrantwise. At first, near the apex of the prothallus, this group of four cells is colourless, but in older organs the cell-walls and the aperture of the neck-canal between them becomes brown in colour, and the archegonia are thus clearly defined in surface view (fig. 15). The neck of the archegonium early projects from the surrounding epidermal cells, and is straight rather than curved. Generally speaking, in older parts of the prothallus the neck has broken short off, so that the characteristic appearance of the group of four cells which surround the aperture of the archegonium

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in these cases is that of the lowest tier of neck-cells. In fig. 15 is shown the head of a small limb of a prothallus with archegonia in different stages of development, in surface view.

There are not lacking signs of dors iyentrality in the distribution of the sexual organs, but these are probably unimportant. For example, the old antheridia are sometimes much more numerous along the edges of the prothallus (in the plane in which it naturally lies), and also at the growing apices the young antheridia sometimes occur more numerously towards the edges. This tendency to dorsiventrality is more apparent still in the fact that in some of the younger prothalli one surface was

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Fig. 16.—Transverse section of limb of prothallus behind growing apex, showing antheridia and archegonia. × 100.

noticed to be almost if not entirely free from rhizoids and sexual organs, whilst the opposite surface bore them both. In the young prothallus shown in fig. 12 one surface was quite naked and smooth, but on the other there were a fair number of rhizoids, and the surface was noticeably rough on account of the protruding of the epidermal cells in a papillose manner, and also at the edges were both rhizoids and antheridia to be seen. These indications of dorsiventrality in the distribution of the sexual organs are not, however, always to be observed, and, on the whole, both antheridia and archegonia may be said to be distributed more or less evenly around the surface.

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Development of the Sexual Organs.

As has been stated in the preceding section, developing antheridia were commonly seen at the growing apices of the prothalli, but only in a very few prothalli did I find groups of young archegonia. In the older regions of the prothallus, where both antheridia and archegonia not infrequently arise singly amongst old organs, I did not find any in the earliest stages of development, though many of both kinds in later stages were to be seen. The fact that the apex of the prothallus is generally very broad militated somewhat against the study of the young developing organs, for transverse sections in this curving region of the prothallus-head cut

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Fig. 17.—Transverse section of main limb of prothallus in older region, showing portions of old sexual organs, also two fertilized archegonia. × 100.

them often obliquely. However, I was able to obtain a fairly good series of both, although certain points must be left for a more complete study.

Perhaps it would not be out of place for me to describe at this juncture the methods adopted for the preparation of my material for microscopic investigation. After the preliminary study and drawing of each prothallus as it was dissected out of the tree-fern humus, it was killed and fixed by immersing for twenty-four hours in a solution of chromo-acetic acid, the formula for which is that given by Chamberlain on p. 21 of his Methods in Plant Histology (3rd ed., 1915). This was found to answer quite satisfactorily so far as the more obvious histology of the prothalli and sexual

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organs was concerned. Some of the material was sectioned by the microtome, but I found that it showed a tendency in the older regions to resist infiltration by the paraffin. I was inclined to ascribe this to the very dense nature of the fungal element. The prothalli of Timesipteris are so firm and large that I decided to hand-cut a number of prepared specimens (having no lack of material) in order to supplement my serial sections with others to as great an extent as possible. I found that, on the whole, the hand-cut sections gave good results, being free from the shrinkage so often associated with the microtome sections. Moreover, they took the stain better. The obvious disadvantage of the hand-cut sections is that they are not kept in

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Fig. 18.—Portion of main limb of prothallus in tangential longitudinal section, showing archegonia. × 70.
Fig. 19.—Portion of main limb of prothallus in transverse section, showing meristematic activity underneath the epidermis. × 137.
Fig. 20.—Transverse section of apex of prothallus, showing single apical cell. × 137.
Fig. 21.—Longitudinal section of apex of slender limb of prothallus, showing single apical cell. × 137.

proper sequence. I used throughout Delafield's haematoxylin as a stain, combining it with safranin for the vascular tissues. This haematoxylin was very satisfactory, especially for differentiating the young embryos. However, this method of staining failed to show anything of the process of spermatogenesis. Campbell (1911, p. 28) recommends using the combination stain safranin and gentian violet for this purpose, as, indeed, generally for prothallial work.

In detecting the youngest stages in the development of the sexual organs one is guided by the fact that they occur in close association with others and also with slightly older organs, and also by the greater size of their

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nuclei and the deeper staining both of these and of their other cell-contents than is the case in the ordinary vegetative cells. They do not arise so near the actual apex of the prothallus as is the case in the Ophioglossaceae or as I have found in the epiphytic prothalli of Lycopodium Billardieri.

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Figs. 22–33.—Series showing the development of the antheridium. × 150.
Fig. 34.—Mature antheridium, showing opercular cell. × 137.

In the development of an antheridium from an epidermal cell the first division wall to be formed is a periclinal one cutting off an outer from an inner cell (figs. 22 to 26). Sometimes the inner of these, and at

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others the outer, is the larger. The mother cell does not at first project beyond the surface of the prothallus, but by the time the first division in it has taken place it has enlarged considerably and has begun to project noticeably. The next division takes place in the outer cell by an anticlinal wall (figs 24, 25). I have no direct information as to the exact sequence of divisions which takes place in the cover-cell, but it is clear that it gives rise to the whole of the outer free wall of the antheridium, whilst from the inner cell is formed the mass of spermatocytes. From figs. 26 and 28 it would seem that a good deal of segmentation takes place in the inner part of the developing antheridium before the outer wall begins to project at all strongly. I did not observe in my preparations any instances of an antheridium in this stage in transverse section, but it will probably be the case that quadrant and octant divisions are formed in the inner cell, as is known in other Pteridophytes. The free wall of the antheridium is never more than one cell in thickness. The mature antheridium projects very strongly beyond the surface of the prothallus as a hemispherical globular body, the number of cells in the free wall being large. From mature antheridia seen in surface view (fig. 14), it is evident that the division walls in the cover of the antheridium intersect one another more or less at right angles, so that the opercular cell is four-sided. This cell is situated at the apex of the antheridium, and is first to be distinguished in surface view by its walls becoming brown in colour (fig. 14). This browning later extends to the adjacent cell-walls, and, before the antheridium has discharged, both walls and contents of most of the cover-cells in the exposed portion of the antheridium have assumed the same coloration. The interior cells of the antheridium rapidly subdivide (figs. 29 to 33), so that a large number of spermatocytes is formed, although the number is not so great as in certain of the Ophioglossaeae and in the subterranean types of Lycopodium prothalli. From the adjacent prothallial cells a wall of more or less flat cells is cut off surrounding the lower portion of the antheridium. The opercular cell seems to vary in size for different antheridia. Rupture of the antheridium is initiated by the disorganization of this cell, while in still older antheridia it is generally to be observed that the cells of the outer wall which adjoin this aperture have also broken down, so that the characteristic appearance of the numerous old discharged antheridia on the main prothallus body is that of small brown saucer-like structures projecting from the surface. The details in the formation of the sperms were not followed. I was unsuccessful in my endeavour to make the sperms swarm in fresh prothallial sections, and the method of staining was not suitable for showing the details of spermatogenesis. Possibly, also, a better killing and fixing solution would have to be sought for this purpose.

The earliest stages in the development of the archegonium are to be distinguished by the very large size of the nucleus in the inner cell. As in the young antheridium, the first wall to be formed is a periclinal by which an outer is cut off from an inner cell. The outer or neck cell divides next by an anticlinal wall (figs. 35, 36), a surface view showing that two such walls are quickly formed intersecting at right angles, so that the archegonium neck-cells have the usual quadrant form (fig. 15). These four cells give rise to the neck of the archegonium, and soon project sharply beyond the surrounding epidermal cells (figs. 36 to 38, and 40). My preparations show that up to this point the inner cell has not divided, but has merely pushed up slightly between the neck-cells along with the

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Fig. 35–49.—Series showing development of the archegonia. Figs. 35–41 × 150; fig. 42 × 137; figs. 43–49 × 150.
Figs. 50a, 50b.—Series of transverse sections through mature archegonium from above downwards. × 137.

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outward growth of the latter. Thus a basal cell to the archegonium is not formed. In figs. 39, 41, and 42 it will be seen that the large nucleus of the inner cell next divides, and a horizontal wall is formed, this (according to my interpretation) cutting off a neck-canal cell from a central cell. This neck-canal cell seems to be evident in the slightly older archegonia shown in figs. 43 and 46. The neck-cells lengthen considerably, and divide by horizontal walls generally two or three times, so that a straight neck is formed (figs. 15, 45, 46) of three or four tiers of cells. The neck-canal cell pushes up between the neck-cells, and probably divides once or twice in the usual way, although I could not demonstrate this, except perhaps in the instance shown in fig. 45 — much less was a ventral-canal cell to be traced. In fig. 15 is shown the rounded apical head of a small prothallus branch on which two archegonia will be seen with protruding necks. In these cases the neck consists of the lowest tier of cells, which have already taken on the characteristic brown coloration, and an upper tier of elongated cells which will divide again by two or three horizontal walls. As soon as the outermost tier separate the neck-canal becomes conspicuously brown. Sooner or later, after the archegonium has matured, the outer three or four tiers of neck-cells fall off, leaving only the lowest tier, whose walls become strongly cutinized. These cells have already assumed the brown colour in their walls, and their nuclei and contents soon do the same. The exposed horizontal walls of this tier of four cells slope inwards towards the canal in a saucer-like form (fig. 15). Although an occasional old archegonium may be seen on the older parts of the prothallus still showing the full length of neck, yet the characteristic appearance of old archegonia is that just described, the four brown rather peculiarly projecting neck-cells, which originally constituted the lowest tier in the neck, surmounting the brown egg-cell (figs. 47 to 49). A close inspection not infrequently shows the remains of the broken-off cell-walls still attached to the outer surface of these persisting neck-cells.

The Development of the Embryo.

Unfertilized old archegonia are abundant on most parts of the main prothallus-body, and are very evident on account of the brown colour of the egg-cell and of the persisting lowest tier of neck-cells. I sectioned a good number of large prothalli on which I found no fertilized archegonia at all, but there were several prothalli on which I found both fertilized archegonia in which the egg-cell had not as yet shown any cell-division, and also several young developing embryos. Also I obtained a number of prothalli which bore single young plantlets in various stages of development, while most of the largest prothalli showed the presence of the ruptured cup-like eminence from which a young plant had become detached. Thus although developing embryos do not occur on the prothalli of Tmesipteris as numerously as in certain of the large terrestrial species of Lycopodium prothallus (vide, e.g., Bruchmann, 1898, p. 37), yet it ought to be possible to obtain a complete series. It was to be noticed that in several instances both the fertilized archegonia and also the developing embryos were grouped, whilst one embryo was found close alongside the point of attachment of a young plantlet. Fig. 17 shows a transverse section of a prothallus in which two fertilized egg-cells are to be seen. It may be noted here that I found Delafield's haematoxylin a satisfactory stain for differentiating clearly the young embryos from the surrounding tissue. After fertilization the egg-cell grows considerably in size (figs. 17, 51, 52)

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Fig. 51.—Longitudinal section of fertilized archegonium. × 175.
Fig. 52.—Longitudinal section of two fertilized archegonia, in one of which segmentation has begun. × 175.
Fig. 53.—Longitudinal section of very young embryo, showing earliest segmentation. × 175.
Fig. 54.—Median longitudinal section of young embryo. × 137.
Fig. 55.—Median longitudinal section of young embryo. × 137.
Fig. 56.—Tangential longitudinal section through upper portion of same embryo as shown in fig. 55. × 137.
Fig. 57.—Median longitudinal section of young embryo. × 137.

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and the nucleus retreats (at first, at any rate) to the inner end of the cell. The ovum surrounds itself with a delicate membrane, which arches up somewhat into the base of the neck-canal of the archegonium and at that point thickens. It grows to a fairly large size before it segments, somewhat, though not to the same extent, as Bruchmann has described in the case of Lycopodium clavatum and L. annotinum (Bruchmann, 1898). The first division wall to be formed is more or less transverse to the axis of the archegonium, and seems to be approximately in the middle of the cell (figs. 52, 53). This wall thus divides the embryo into what we may speak of as the lower and upper regions. This first division may be clearly traced afterwards in older embryos. The next division wall to appear is in the lower half, and extends at an angle from the first wall to the lower end of the embryo (figs. 52, 53). It also may be clearly seen in older embryos. No embryos were found in transverse section, so that this description of the earliest stages in segmentation can only refer to the appearance of the embryo in longitudinal section. Still older embryos are shown in figs. 54, 55, and 57. I find it difficult to describe with any degree of certainty the sequence of segmentation which has taken place either in the lower or in the upper parts of these embryos.

In addition to the section of the embryo shown in fig. 55, already referred to, a second section (fig. 56), obviously not so nearly median, shows a part of the same embryo which I am inclined to think is the stem-rudiment. In it there are two main walls intersecting at right angles, and in one of the cells so formed another wall has appeared cutting out what might well be an apical cell. This part of the embryo took the haematoxylin stain rather more darkly than did the rest, and the nucleus of the “apical” cell was conspicuously large, the suggestion being that this part was forming rapidly. It will be evident from a comparison of the two sections of this embryo that this portion which we are now considering belongs to the upper region and has arisen laterally from it. If it proves to be correct that the shoot originates from the upper half, this fact would distinguish the embryo of Tmesipteris from that of the Lycopodinae, where the upper primary segment constitutes a suspensor, but would, on the other hand, suggest the embryo of Equisetum and the Ophioglossaceae. Of course, one main reason why the embryo of Tmesipteris is likely to prove of special interest is the fact that the adult plant has no root, consisting only of an underground branched rhizoid-bearing rhizome and an aerial branched leaf-bearing portion. Anticipating here what I shall be bringing forward in connection with the developing plantlet, we may say that the young plant of Tmesipteris is “all shoot,” just as the embryo of certain members of the Ophioglossaceae has been described as “all root.” The question naturally arises whether there is in the embryo of Tmespteris anything which may be interpreted as the undeveloped rudiment of a root. Only a much fuller study of the development of the embryo than that given above can satisfactorily decide this point. I hope to be able to gather more material for such a study. The stages described above stop short at a most interesting point, and I have found it difficult to interpret some of them. Keeping pace with the growth of the embryo, the surrounding prothallial cells rapidly subdivide, so that the embryo is enwrapped by a small-celled tissue which soon begins to project as an eminence from the side of the prothallus (figs. 55, & c.).

Before passing on to the section of this paper which deals with the developing plantlet there is still an important and interesting point to be brought forward which concerns the question of the “foot” of the

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Plate II.
Longitudinal section, prothallus of Tmesipteris, showing young plant attached.
(Photomicrograph.)

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Plate III.
Longitudinal section, point of attachment of young plant of Tmesipteris to the
prothallus. (Photomicrograph.)

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embryo. Longitudinal sections through the point of attachment of a young plantlet to its parent prothallus, such as that shown in figs. 58, and 59, and in Plates II and III, in all of which the plant-axis is in transverse section, but the foot in longitudinal section, reveal the fact that the region of the plantlet which is in immediate contact with the prothallial tissues—i.e., the “foot” or absorbing region—is prolonged into a large number of long haustoria-like processes, which penetrate the tissues of the prothallus and evidently function as absorbing organs. These processes are generally two cells wide at their base, whilst the forward end of each is prolonged into a row of single cells, the terminal cell of the row being more or less elongated and rounded. They emanate, appearing in section like the fingers of a hand, from a region which consists largely of cells which are dividing. The cells both of the processes and of the region from which they arise stain very conspicuously with haematoxylin both in their walls and nuclei. In transverse section the processes are circular in outline. This will be seen in fig. 60, which also shows the nature of the surrounding prothallial cells. On the side towards the plant-axis the cells gradually increase in size, and median sections through the whole plant-foot reveal the fact that vascular tissue, both xylem and phloem, extends from the plant-axis into the foot. In fact, longitudinal sections of detached plantlets of similar age such as that shown in fig. 68 indicate that the entire vascular bundle of the young plant inclines at an angle into the foot. The obvious explanation would be that at an early stage in the development of the young plant

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Fig. 58.—Transverse section of young plantlet through point of attachment to prothallus, showing foot and haustorial outgrowths. × 42.

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an apical meristem is set apart from which a plerome strand arises, and that this strand of tissue functions solely in the transportation of food from the parent prothallus up to the growing apex of the shoot. There is nothing to indicate a possible root-rudiment. The haustorial processes are many in number, and no one of them more than any other could be suspected of being such a degenerate or arrested root organ. There is also the broad zone of meristematic cells lying between these processes and the axis of the plant. Of what nature is this ? Only a series of embryos more complete than that described in this paper can indicate at all satisfactorily the first differentiation of the embryo into shoot and foot, and whether or not a root-rudiment is present. If the shoot develops from the lower half of the embryo, then there would necessarily have to be a curvature in the forward growth of that region (as in the Lycopodium embryo) so as to allow the shoot to emerge, as it certainly does, at the apex of the prothallial eminence on which the embryo has been developing. The segmentation in the upper primary half of my embryos is certainly not as clear and regular as it is in the epibasal region of the Equisetum embryo, which there gives rise to the shoot-axis; but, on the other hand, it does not suggest the Lycopod suspensor. My own opinion, based upon the study of the embryos described in this paper and of the young plantlets, is that the shoot arises from the upper region (i.e., nearest the arche-gonial neck), and that the lower half gives rise only to the foot, the surface cells of the latter growing out into the peculiar haustorial processes. I see nothing to indicate a root. There is no cotyledon, the first leaves being formed at a very late stage as mere scales from the apical cell of the shoot after the latter has emerged from the surface of the humus and has changed its character from a rhizome to a green aerial stem.

A still younger plantlet than that just described is shown in median longitudinal section in figs. 61 and 62. The shoot took the form of a globular protuberance from the surface of the prothallus. Sections through the foot showed that the characteristic haustorial outgrowths were only in the first stages of formation. The spherical shoot showed at one point a slightly conical projection, which in section was seen to be composed of meristematic tissue. This was obviously the actual apex of the shoot, but no vascular strand had as yet arisen from it. The main portion of the shoot consisted of large uniform cells in which the coils of the mycorhiza were already established. The apical region consisted of smaller regularly arranged cells, free from fungus, and showing conspicuous nuclei. I was not able to distinguish whether or not there was a single apical cell present. Fig. 61 shows the plant as a whole in median longitudinal section, but the shoot-apex is cut somewhat obliquely, as its direction of growth did not coincide with the plane of the section. From a study of this particular plantlet I am still more of the opinion that the embryo gives rise to two main organs only—viz., the foot and the shoot—the former arising from the lower half and the latter from the upper. Whether or not a definite stem-apex is differentiated early in the embryo my material does not show, although the embryo shown in fig. 56 would seem to indicate this.

Developement of the Young Plant.

A good number of prothalli were found on which single. young plants in various stages of development were borne. Also, I dissected out of the tree-fern humus a large number of complete plantlets which had become

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Fig. 59.—Section through point of attachment to prothallus of same young plantlet as shown in fig. 58, to show manner of detachment of plant from prothallus. × 42.
Fig. 60.—Tangential section through foot of young plantlet shown in fig. 58, showing haustorial outgrowths in transverse section. × 125.
Fig. 61.—Median section through very young developing plantlet, showing foot and apical region. × 84.

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detached from their parent prothalli. I am thus able to give a connected account of the development of the young plant. The earliest stages, in which the young shoot has just broken through the surface of the prothallus, and before a vascular strand has made its appearance (see fig. 61), has been described at the end of the last section. The shoot-apex in this particular plantlet had already been differentiated, though precisely at what stage in the development of the embryo I cannot say for certain. The subsequent elongation o the originally spherical shoot takes place at this apex. In figs. 64 and 65 are shown two early stages in the development

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Fig. 62.—Section through foot of same young plantlet as shown in fig. 61, showing outgrowth of epidermal cells of foot. x74.
Fig. 63.—Transverse section of young plantlet similar to that shown in fig. 68, showing initiation of secondary apex of growth. × 64
Fig. 64.—Very young detached plantlet, showing apex of growth, and fragment of prothallial tissue attached to foot. x18.
Fig. 65.—Very young detached plantlet, showing foot and both primary and secondary apices of growth. x16.
Fig. 66.—Young developing plantlet attached to prothallus; secondary apex of growth not yet developed. x8.

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of the young plant, in these cases the plantlets having become detached from their parent prothalli during the process of dissection. I have no plantlets of this age in section, but judging from its conical and somewhat pointed shape I would say that the actual apex is occupied by a single apical cell. That end of the young plant which is opposite to the growing apex is obviously the “foot” or absorbing region, where the plant was in connection with the prothallus. In the detached plantlets shown in figs. 64 and 65 this end is roundish in outline, it being evident that the haustoria-like processes of the foot had been left embedded in the tissues of the prothallus. Still older plantlets consist of a lengthening undifferentiated rhizome, golden-brown in colour, thickly clothed with long straight golden-brown rhizoids. Where the rhizoids are broken off, characteristic ring-like outgrowths are left projecting slightly from the epidermal cells. The latter are brown in colour, and, owing to the clear colour of the rhizome generally, stand out very distinctly in outline. The original point of attachment of a detached plantlet of this age to its parent prothallus can always be readily distinguished as a dark circular patch situated on a slight but distinct conical prominence at the basal end of the rhizome. Sometimes there is a brown fragment of prothallial tissue which may show old sexual organs still attached to this foot-prominence.

The manner of detachment of the plant from its prothallus may best here be described. It was found during the process of dissecting that the plantlets very easily become detached from their parent prothalli. Reference to the longitudinal section of the plantlet and prothallus given in fig. 59 will show that a saucer or cup-shaped line of dehiscence extends from the edge, where the developing plant has ruptured the tissues of the prothallus, down into the central regions of the foot. This line of dehiscence is clearly marked out by the browning of the cell-walls along the line. Figs. 58 and 59 show clearly both how readily the plant can become detached from the prothallus, leaving behind in the tissues of the latter the haustoria-like processes, and also how the large cup-like point of attachment, which so often is a characteristic feature on full-grown prothalli, comes to be formed.

All the youngest plantlets found, whether detached or still in connection with the prothallus, showed only one apex of growth, the other end of the plantlet being bluntly rounded and in no way differing in external appearance from the rest of the rhizome surface (figs. 66 and 67). The point of attachment to the prothallus was at this undifferentiated end of the plant. Longitudinal sections of the prothallus and plant shown in fig. 66 revealed that there was nothing at this end of the plant to indicate an apex of growth. Sooner or later, however, a new apex of growth is differentiated at this point (figs. 1, 68, 69), and the young rhizome then proceeds to grow in length in a direction more or less exactly opposite to the primary direction of growth. This new portion of the plant-rhizome is sometimes in a straight line with the first-formed shoot axis (fig. 70), but more often is inclined to it at an angle, the brown point of attachment in the latter case being then to be seen on the angle (figs. 65, 69, 71). In some instances this secondary apex of growth was not differentiated until the plant had attained a considerable size (figs. 67, 68, 69), but in others, again, it was differentiated early (fig. 65). In fig. 1 is shown a plant attached to its prothallus in which the main shoot had a very irregular and peculiar appearance, and at the base of

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which the new apex of growth could be seen. In longitudinal section it was seen that the rounded protuberance at the base of the plant shown in fig. 68 was formed by a surface group of actively dividing meristematic cells (a single apical initial could not be traced), and that from this meristem a plerome strand connecting with the central strand of the plant was in process of formation (fig. 63). Also it was seen that two tracheides were leading out from the centre of the plant-axis towards the new apex. Thus we may say that the development of the new axis of growth is adventitious, and may compare it with the well-known adventitious origin in the epidermal and outer cortical cells of older rhizomes of groups of meristematic cells which are frequently to be observed either in a state of arrested development or about to develop into lateral buds. It must, however, be noted that whereas these lateral buds are not confined to any part of the rhizome, but appear in a quite haphazard manner, the secondary apex of growth in the young plantlet is always differentiated in the one position. Thus there is no root to be distinguished in the young plant of Tmesipteris, there being developed, both above and below the original foot, a rhizome identical in the two cases in appearance, function, and manner of growth.

A series of transverse sections through the foot of a young plant which consists of both primary and secondary rhizome portions—such, for example, as that given in fig. 72—shows that there is a continuous vascular strand throughout the whole rhizome, identical in structure in the two portions of the rhizome, and unbroken in the foot region. Before the secondary apex of growth is differentiated in the young plant the vascular strand inclines bodily into the foot. When the new apex is formed a plerome strand is differentiated from it, and it would appear that this joins on with the primary strand at the angle where the latter inclines into the foot. Possibly the first vascular elements in this secondary strand are actually formed from the angle of the primary strand in connection with the transport of food from the prothallus to the new apex. In fig. 63 is shown the stage at which the plerome strand of the secondary portion of the rhizome is in its earliest development, but vascular elements seem to be leading out to meet it from the point where the strand of the primary part of the rhizome leads down into the foot.

The growing apices of the young developing plantlets are whitish-grey in colour and more translucent than the rest of the rhizome, and are often slightly swollen. In this respect, and in the general appearance of the young rhizome, there is a certain similarity between detached portions of prothalli and of young plants. The fungal coils are present in the cortical cells of young plants which are still attached to their prothalli, but apparently the fungus does not spread from the prothallus to the plant, but the latter is early infected through its rhizoids. Several of the young rhizomes bore short swollen lateral shoots (fig. 72), clear or almost light-green in colour, and one frequently noticed on the rhizomes of both young and older plants points of meristematic activity. Besides this adventitious method of branching, the rhizome-apex may fork dichotomously (fig. 75). Sooner or later one or other of the main ends of the young rhizome grows upwards as an erect aerial shoot, losing its rhizoids and decreasing in thickness in the transition region. The aerial shoot is at first whitish in colour and is quite devoid of both rhizoids and scale leaves, but at length its apex becomes green and gives rise to the first scale leaves (figs. 5, 73, 74). After a few of these scale leaves have been formed,

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larger leaves of the characteristic form take their place. Both ends of the young rhizome may in some cases emerge from the humus as aerial stems (fig. 73). The actual apex of the young aerial shoots is slender and sharply conical (figs. 5, 73, 74), and even in surface view under a low power of the microscope the single apical cell can be seen. In longitudinal section the apical cell and the order of segments cut off from it is almost diagrammatically clear (fig. 77). The broader apex of young rhizomes also shows a single apical cell (fig. 76). In several instances young plants of a considerable size, showing differentiation into both subterranean and aerial portion, were found still attached to their prothalli, the latter being in some cases firm and healthy (figs. 5, 73), and in others old and withered (figs. 9, 10).

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Fig. 67.—Young detached plantlet, showing fragment of prothallial tissue attached to foot; secondary apex of growth not yet developed. × 8.
Fig. 68.—Young plantlet attached to prothallus, showing secondary apex of growth. x5.
Fig. 69.—Young detached plantlet, showing foot and secondary apex of growth. x7.
Fig. 70.—Young detached plantlet, showing foot and also primary and secondary apices of growth on either side of foot. The two apices are not inclined to one another at an angle. × 8.
Fig. 71.—Young detached plantlet, showing foot and also primary and secondary regions of rhizome on either side of the foot. × 6.
Fig. 72.—Young developing complete plant, showing foot and also lateral bud; the latter and the two apices are swollen. × 4.

Development of the Vascular Anatomy.

The anatomy and morphology of the adult plant of Tmesipteris has already fairly recently been described by Miss Sykes (1908), so that there is no need for me to go over this ground again. Miss Sykes's material came from New Zealand, and she notes that it comprised two forms which

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had previously been separated by some writers as two species—viz., as T. tannensis and T. lanceolata. She gives figures of the aerial stems of these two forms. In the section in the present paper which deals with “Occurrence and Habit” I noted the fact of these two forms, and indicated that the prothalli and young plants which I had obtained belonged to the form which grew to the greater size and had the more pendulous and flaccid habit and possessed the larger leaves. This is the form referred to by Miss Sykes as T. lanceolata. Cheeseman (1906) does not recognize more than the one species in New Zealand, to which he gives the general name T. tannensis, although in a note he adds, “By some authors it is split up into three or four, distinguished mainly by the shape of the apex of the leaf (which I find to be variable even in the same individual) and by certain histological details, the constancy of which has yet to be established.” I have not had access to the papers referred to by both Miss Sykes and Mr. Cheeseman as setting forth the exact morphological and histological details on which the distinction is drawn between the different forms of Tmesipteris, so cannot refer particularly to them. However, I shall be noting in this section of my paper certain details in the stem-structure of the two forms referred to above.

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Fig. 73.—Complete young plant, showing parent prothallus, foot, lateral bud, and also both ends of rhizome developed into aerial stems. × 2.
Fig. 73a.—Apex of smaller aerial stem shown in fig. 73. × 9.
Fig. 74.—Apex of a young aerial stem, showing initiation of leaf-formation. × 9.
Fig. 75.—Apex of rhizome of young plant, showing dichotomy. × 10.

Having an abundance of young plants of Tmesipteris of the form T. lanceolata of all stages of growth, I made a study of the development of the vascular cylinder of both the rhizome and the aerial shoot. I have no serial sections of the youngest plantlets, such as those shown in figs. 64

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and 65, in which the differentiation of vascular tissue between the shoot-apex and the foot would be in its earliest stages. Transverse sections of plantlets of the same age as that shown in fig. 68 are given in figs. 78, 79, and 80 There is a slight central strand consisting of, in the one case, one, and, in the other, two, narrow scalariform tracheides placed more or less collaterally with a group of darkly-staining phloem elements.

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Fig. 76.—Longitudinal section of apex of rhizome of young plant shown in fig. 5, showing single apical cell. × 140.
Fig. 77.—Longitudinal section of apex of aerial stem of young plant shown in fig. 5, showing single apical cell. × 140.
Fig. 78.—Transverse section of stem of young plant similar to those shown in figs. 66–68. × 50.
Fig. 79.—Transverse section of stele of stem shown in fig. 78. × 200.
Fig. 80.—Transverse section of stem stele of another young plant. × 200.

There is an endodermis in which the characteristic radial markings are clear. The cortex is uniformly parenchymatous and harbours the fungal coils more especially in its middle zone, whilst the epidermis is cuticularized and individual epidermal cells are prolonged into rhizoids. Longitudinal sections of a young prothallial plantlet similar to that shown in fig. 68 revealed the fact that the vascular strand of the shoot curved bodily round at the base of the plant into the foot, where it ended blindly. From

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sections of the plant and prothallus shown in fig. 66 it was clear that even at this early stage the peculiar brown deposit referred to by other writers in their studies of the mature rhizome of Tmesipteris and Psilotum is present in its first beginnings in the innermost layer of cortical cells. The rhizome and the aerial stem of the plant shown in fig. 5 were similar to each other in their vascular structure, three or four xylem elements lying more or less collateral with a group of phloem. The fungal element was present in the cortical cells of the rhizome but not of the aerial stem, and in neither case was the brown deposit to be seen. The endodermis was here not so clearly defined as in younger plants. A transverse section of the rhizome of a slightly older plantlet is given in fig. 81, and shows that here the single group of xylem elements is placed centrally in the midst of the darkly-staining phloem, the metaxylem having been formed centripetally. Immediately surrounding the phloem are one or two layers of larger cells, probably to be identified as pericycle and endodermis, whilst the cortex is slightly collenchymatous and its innermost layer shows marked evidence of the brown deposit. The middle cortical zone contains the mycorhizal coils, while the outer surface and the rhizoids had the

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Fig. 81.—Transverse section of stele of rhizome of young plant. × 160.
Fig. 82.—Transverse section of stele of rhizome of medium-grown plant. × 125.
Fig. 83.—Transverse section of stele of large rhizome of plant shown in Plate I. × 125.
Fig. 84.—Transverse section of stele of aerial stem of young plant shown in fig. 85. × 125.

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same brown coloration as has the peculiar deposit already referred to. In the vascular cylinder of a medium-grown rhizome, sectioned at some distance behind the apex, there is a tendency for thin-walled elements to invaginate the centrally placed group of xylem (fig. 82), and in some sections it was seen that it had separated it into two groups. In these rhizomes the brown deposit can be seen in all stages of formation, and it may be detected also in individual cells in the middle cortex, while the fungal coils have almost disappeared from the cortical cells. In fig. 83 is shown the vascular cylinder of the largest ground-growing rhizomes of the form T. lanceolata obtained by me in Stewart Island. Here the xylem is definitely split up into two main curving plates more or less surrounding a central group of thin-walled elements. The comparison of a number of sections showed that the configuration of these xylem groups was constantly changing, sometimes two adjacent ends of the groups joining, and at other times one or both of the two main groups subdividing so that the number became three or four. It would seem, then, from a comparative study of the rhizomes of plants of different ages, that along with the increase in number of xylem elements in the central cylinder there is a diminishing disposition on their part to cohere in one group, so that the original monarch condition becomes lost and the xylem is disposed in separate plates or groups in the midst of the phloem, the tendency being in the oldest rhizomes for these groups to be arranged more or less in the form of a ring surrounding a central group of thin-walled (so-called “pith”) elements. It must be noted that this alteration in the xylem-grouping is in no wise occasioned by any branching of the stele. In these very large humus-growing rhizomes also it was seen that the fungal element was almost entirely absent from the cortical cells, nor did the latter show any signs of thickening at their angles.

The development in size and configuration of the rhizome stele corresponds in a general way to what Miss Sykes (1908) has described in the gradual differentiation of the stele behind the growing apex of the mature rhizome, except that she refers the splitting-up of the original single xylem group into two or more groups only to the transition region between rhizome and aerial stem. Her material probably did not include such large-sized rhizomes as those examined by me.

As I have stated above, in the youngest plantlets which show differentiation into both aerial stem and underground rhizome the vascular cylinder is identical in configuration in both. The stele is monarch, the xylem group containing from two to six scalariform elements. In aerial stems of slightly older plants, however, there is a marked change, the characteristic structure of the adult aerial stem, with its separate mesarch xylem strands, beginning to manifest itself. A transverse section of such a young stem shows the pressure of large adherent leaf-bases forming conspicuous angles to the section (fig. 85), the cortical tissue in the angles containing abundant air-spaces. In the central cylinder there are two groups of xylem, obviously mesarch, on the outer side of each of which is phloem, whilst the tissue separating the two groups has the appearance of ordinary parenchymatous cells (fig. 84). I could not identify endodermis or pericycle. There are in young stems of this age no leaf-traces, the leaves as yet being no more than scale leaves. There is, of course, as in all aerial stems, no fungus present. Again, in the aerial stems of still older plants there are to be seen three such separate groups of xylem (figs. 86 and 87) placed in the form of a triangle, the position of the xylem

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groups corresponding to the leaf-bases. There is a very slight leaf-trace, consisting of a few narrow phloem-like elements with no xylem. The cortical cells are still thin-walled, but in some sections it is apparent that the phloem and the other parenchymatous elements in the central cylinder are beginning to show a slight thickening of their walls. Lastly, in figs. 88 and 89, are shown the steles of the aerial stems of more mature plants, in which there are five mesarch groups of xylem. In the largest aerial stems of all there is a tendency for neighbouring groups of xylem temporarily to join together, thus forming curving plates (fig. 89). In these oldest stems the phloem and the “pith” elements are partly lignified, as has been described by Miss Sykes (1908, p. 70). In fig. 90 is shown a single xylem strand, illustrating its mesarch character and the lignified nature of the surrounding elements. The leaf-trace is collateral, and consists of two or three xylem elements and a group of phloem (fig. 89). I must remark again that the plants of various ages which I examined, and which are described above, all belonged to the particular form of Tmesipteris referred to as T. lanceolata In none of the aerial stems of this form did I find the cortex collenchymatous, or the presence of the brown deposit in its innermost cells. This is in contrast with what Miss Sykes states in her paper (1908, p. 70), for she found

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Fig. 85.—Transverse section of aerial stem of young plant. × 46.
Fig. 86.—Transverse section of stele of aerial stem of young plant shown in fig. 87. × 140.
Fig. 87.—Transverse section of aerial stem of young plant. × 46.

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both these characters present in the aerial stems. I sectioned also some material, obtained from a tree-fern, which presented a very typical example of the form illustrated by Miss Sykes as T. tannensis The aerial stem was short and suberect and very compact in habit, and the rhizome firm and brittle. A transverse section taken towards the base of this particular

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Fig. 88.—Transverse section of aerial stem of mature plant. × 60.
Fig. 89.—Transverse section of aerial stem of mature plant, showing coalescence of neighbouring xylem groups into bands, and also a leaf-trace. × 60.
Fig. 90.—Transverse section of single xylem group in stele of aerial stem of mature plant. × 175.
Fig. 91.—Transverse section of base of aerial stem of mature plant of Tmesi-pteris tannensis which showed characteristic short erect xerophytic habit, showing strongly lignifled cortex and presence of brown deposit. × 50.
Fig. 92.—Longitudinal section of stele of rhizome of same material as that indicated under fig. 91, showing method of deposition of brown substance in inner cortical cells. × 70.

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stem is shown in fig. 91, in which it will be seen that the cell-walls of the entire cortex are strongly thickened (taking both the safranin and the haematoxylin stain) and that the brown deposit is also present. In fig. 92 is shown the vascular cylinder of the same region of the stem in longitudinal section, in which there is a good example illustrated of the progressive method of deposit of the brown substance in the inner cortical cells. The conclusion I would draw is that whereas the general configuration of the vascular tissues is the same for both forms, T. tannensis and T. lanceolata, as regards both the rhizome and the aerial stem, yet there are certain less important but constant histological differences between them. The rhizome of T. tannensis does not attain as large a size as that of the loose-humus-growing T. lanceolata and hence does not show the same extent of development of vascular tissues with the consequent splitting-up of the xylem into constantly changing groups. Also, in the drooping aerial stem of T. lanceolata there is an absence of the thickening of the walls of the cortical cells and of the formation of the brown deposit, both of which features are present in the more xerophytic stem of T. tannensis. From the present study it would seem that there is no great difference between the stele of the rhizome and that of the aerial stem, and this one would expect, seeing that they are merely different regions of the plant-shoot, differing only in function. Any of the rhizome-branches are able to emerge from the surface of the humus and develop leaves. In the youngest plantlets the shoot is all rhizome, and one or both ends of it turn upwards and acquire the aerial habit. The rhizome portion functions largely probably as a storage organ, bearing rhizoids, harbouring an abundant mycorhiza, and showing the presence of starch in the cortical cells. The aerial stem shows an absence of all these characters, but the comparatively large leaves, with their strongly decurrent bases and the fertile structures, constitute its dominant feature. In the youngest plants the configuration of the vascular tissues is identical in both rhizome and aerial region. In both, as the number of vascular elements increases, there is manifested a disposition for the xylem to arrange itself in groups surrounding a central “pith,” this being more marked and definite a feature in the aerial stems, probably on account of the influence of the leaf-trace system. In the aerial stems the xylem strands are characteristically mesarch, and Miss Sykes has shown that this is so also in those parts of the rhizome where the xylem is arranged in separate strands. In both there is a disposition for neighbouring xylem strands to coalesce to form curving plates of tissue surrounding the central pith as by a broken ring. Thus the nature of the full-grown stele throughout the Tmesipteris plant, and the manner of its development both at the apex of the mature rhizome and in the young plant, from the monarch or collateral condition, through the stages of diarch, triarch, and quadrarch to the ring-like condition, may be closely compared with the form and development of the stele in the adult plant of Psilotum triquetrum such as Miss Ford (1904) and Mr. Boodle (1904) have described it. In his paper Boodle traces the similarity between Tmesipteris and Psilotum with regard to the stem-anatomy, and shows that one great point of difference between them—viz., the mesarch structure of the xylem strands in the aerial stems of the former—to a certain extent breaks down owing to his discovery of isolated instances of mesarch structure in the lower regions of the aerial stem of Psilotum.

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In view of the fact that Boodle and others have found secondary xylem in the transition region of the stem of Psilotum, I closely examined the stems of Tmesipteris from this point of view, but found there no traces of it. Also, it may be mentioned that I did not find any evidence of vegetative propagation in Tmesipteris corresponding to the formation of bulbils (Brutknospen) described by Solms-Laubach (summarized in Engler and Prantl, 1900, pp. 612–14) for Psilotum. The long aerial stems of T. lanceolata are sometimes branched, but I did not examine the branching of the stele. It is interesting to note that on the fertile stems the sporophylls occur in clearly defined regions corresponding to the habit so well known in Lycopodium Selago, and that on the longest stems as many as five or six such fertile regions may sometimes be observed separated from one another by sterile regions.

Comparative Remarks.

It now remains for me to compare the prothallus and young plant of Tmesipteris as described in this paper with what has already been brought forward by other writers with regard to the gametophyte generation in the Psilotaceae, and also to include in this comparative survey certain other pteridophytic types of prothallus.

Lang's prothallus (1904), which he has provisionally assigned to Psilotum, conforms to a type which certainly differs markedly from that of Tmesipteris as described by Lawson and in the present paper. The differentiation of the prothallus into vegetative and reproductive regions with the meristem located between them, the organization of fungal zones and their evident influence upon the form and structure of the prothallus, is in striking contrast to what has been described for Tmesipteris. This we would probably not have expected, considering the strong morphological and anatomical resemblances between the two genera with respect to the adult plant. And yet, after all, there is not much greater difference between Lang's prothallus and that of Tmesipteris than what there is between, for example, the subterranean and the epiphytic types of Lycopodium prothalli; and we have come to look upon the latter as being but different modifications of a common fundamental structure of Lycopodium prothallus. Lang notes that the prothallus described by him is “practically identical with [that of] Lycopodium complanatum” (1904, p. 576), and goes on to show that it would not be surprising if the prothallus of Psilotum were of the subterranean type, for it commonly grows as a terrestrial plant as well as an epiphyte. Apparently he did not obtain from this single prothallus any information with regard to the archegonium or embryo; but as regards the structure of the antheridium there is certainly a great difference between what he has described and what is now known in the case of the antheridium of Tmesipteris. However, there is nothing to be gained by drawing out any further this comparison, for Lawson (1917A, p. 786) states that he has discovered “a single specimen of a structure that he believes to be the prothallus of Psilotum … [and that this] bears no resemblance to the supposed prothallus described by Lang.” In a later paper he has described the prothallus of Psilotum, but this account I have not yet seen. The point that I wish to emphasize here is that in view of the remarkable diversities in form and structure known amongst the prothalli of the various species of Lycopodium we cannot regard the fact of the great difference in these respects between Lang's prothallus

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and that of Tmesipteris as constituting a valid argument against the possibility of the former belonging to the Psilotaceae.

I must enter more into detail in comparing Lawson's observations on the prothallus of Tmesipteris with my own, because although it will be clear that they correspond in many particulars, yet it will be just as obvious that the two accounts differ in many other respects.

First of all, then, with regard to the similarities in the two accounts. The prothallus is shown in both to be subterranean and saprophytic in habit, of a characteristic brown colour, and covered with numerous long rhizoids. It is cylindrical in form, is not differentiated into reproductive and vegetative regions, and can branch. There is an endophytic fungus which is found in any part of the prothallus-body and is not localized in definite zones. The antheridia and archegonia are intermixed, and are distributed in large numbers over practically all parts of the surface of the prothallus. The two accounts of the structure of the mature sexual organs are closely similar. The embryo is carried on a distinct protuberance of the prothallial tissues, the result of localized meristematic activity in the cells of the latter keeping pace with the development of the embryo. The embryo shows a hypobasal and an epibasal portion, the latter being characterized by a peculiar development from its surface of lobes or protuberances. This general similarity in the two sets of prothalli and their essential organs might be sufficient to show that they both belong to the same order, Psilotaceae, or even also to the same genus, Tmesipteris.

But there are also some very striking differences between them which must be considered. To begin with, Lawson states that, “compared with the Lycopodiales and other Pteridophytes, the prothallus of Tmesipteris is small.” His largest specimen measured only ⅛ in. in length. My prothalli, except the very youngest, were very large compared with this, several of the largest being up to ⅝ in. in length. The tissue of Lawson's prothalli “is extremely soft and fragile,” and easily destroyed in the process of cleaning with a camel's hair brush, whereas my prothalli are firm and solid and thick, and are very favourable objects for hand-sectioning in elder-pith. A small but striking point of difference lies in the fact that Lawson describes the rhizoids as characterictically twisted, but in my figures they are shown as perfectly straight. Lawson speaks of the endophytic fungus as being “more conspicuous in the surface cells and those near the surface,” although it may extend into the very interior of the prothallus. I found that it was only in the oldest and lowest regions of the prothallus that the fungus inhabited the epidermal cells and those of the cortex immediately underlying it, but that it was uniformly present throughout the prothallus-body (except, of course, at the growing apices) in the more centrally placed cells. A comparison of figs. 1, 2, and 3 in Lawson's paper with any of those in mine which show the complete prothallus will reveal a noticeable difference in the fact that in the latter cases there is always a bluntly rounded apex to each branch of the prothallus, the growing apices usually taking the form of a swollen head, whereas in the former the ends of the branches are shown (if not broken) as pointed structures. It will be noticed that these differences between the two accounts relate entirely to the external form of the prothallus and the disposition of the fungal element. The appearance and structure of the mature sexual organs is identical in both accounts. I must here point out that the archegonia as seen and figured by Lawson, and described by him as being very simple and peculiar, are only the old organs which, as has been shown in the present paper, have lost the upper tiers of reck-cells.

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If it were not for the fact that in Lawson's figures of the prothallus some of the pointed ends of the branches are shown as complete and unbroken, I would be inclined to think that his specimens were merely fragments of old prothalli and not complete ones. All the points of difference enumerated above seem to point to this; and there is another fact which bears upon the same point—viz., that in none of the prothalli figured by him does he show a meristematic region. There is, however, quite another explanation of the differences between our prothalli, which is that whereas mine belong to the form sometimes spoken of as T. lanceolata, which, as I have shown, differs from the other form, T. tannensis, not only in general habit but also in certain histological details, Lawson speaks of his prothalli as those of T. tannensis. We have become so familiar with the fact of the manifold variations in the types of prothallus of the different species in the genus Lycopodium—new variations being found in almost each additional species discovered—that it is not unlikely that the prothalli of Tmesipteris as described in the two accounts will be found to be those of two different forms which have hitherto been grouped under the collective name T. tannensis. The fact that Lawson's prothalli were obtained by him almost singly from widely different localities and in different years indicates that they represent a constant type of prothallus.

The prothallus of Tmesipteris shows certain resemblances, such as its cylindrical, radially symmetrical, and more or less drawn-out form, its apical growth, and its branching, to certain other pteridophytic types of prothallus, such as those of the epiphytic Lycopodiaceae and Ophioglossaceae and Helminthostachys. But these resemblances are only what might be looked for in prothalli having the same epiphytic habit. Even with regard to these general characters the resemblance does not hold quite closely, whereas in the matter of other main features, such as the nature of the basal (or “primary tubercle”) region, the distribution of the fungal element, and the differentiation of vegetative and reproductive regions in the prothallus, there are striking differences. Thus on a general sum of characters the prothallus of Tmesipteris stands apart from that of both the Ophioglossaceae and the Lycopodiaceae. Still less does it show any evidence of affinity to the prothallus of Equisetum. This conclusion is strengthened by a comparative study of the sexual organs, embryo, and young sporophyte. The antheridium is strongly projecting in a manner almost resembling that of the male organ of the leptosporangiate ferns, whereas that of the Ophioglossaceae and Lycopodiaceae is sunken. However, in the manner of its development it agrees with that of the two latter orders. The archegonium also is peculiar in that there is apparently no basal cell cut off in the young rudiment, and the form of the mature organ is very characteristic. It is not certain from which primary half of the young embryo the shoot and the foot respectively develop, or whether there is or is not a suspensor present. But the peculiar development of the foot into long haustoria-like processes, the total absence of a root, and the dominance of the shoot mark out the embryo of Tmesipteris as bearing very little resemblance to that of any other class of Pteridophytes. From the single embryo found by him in which three lobes were present on the lower half Lawson is inclined to interpret one of these lobes to be the rudiment of the root, ascribing the others to the foot. The fact that in older stages there are a large number of these lobes present, and that they are all similar in appearance, seems to me to indicate that they are nothing more than haustorial outgrowths; and this would also appear to be borne

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out by the fact that the vascular strand of the shoot is in close connection with them. However, their early appearance in the young embryo is noteworthy. Lawson's embryo presents an interesting stage slightly older than those described in the present paper, but there is still a gap in the series which conceals the first differentiation of the young stem-apex, although such very young plantlets as those shown in figs. 61, 64, and 65 in the present paper seem to indicate that the shoot arises from the hypobasal portion of the embryo.

Scott (1900, p. 499) first pointed out the similarity between the sporophyll of the Psilotaceae and that of the Sphenophyllales, and repeated his statements more fully in the second edition of his Studies (1909, pp. 626–31). Thomas (1902) strengthened this idea by showing that the nature of the frequent abnormalities which occur in the sporophylls of both Tmesipteris and Psilotum bring those structures nearer still to those of certain of the Sphenophyllales and especially to that of Cheirostrobus. Miss Sykes (1908) has also supported this with additional evidence by her elucidation of the vascular structure of the sporophyll and synangium of Tmesipteris. Both Bower (1908) and Seward (1910, p. 14) have accepted the suggestion of the affinity of the modern Psilotaceae with the fossil Sphenophyllales.

A general similarity in vascular structure in the mature plants of Tmesipteris and Psilotum has been pointed out by various writers, and, as described in the present paper, the study of the development of the stele in both the rhizome and aerial stem of Tmesipteris helps to make the nature of this structure more clear. Scott (1900) noted the similarity between the stem-anatomy of the Psilotaceae and that of the Sphenophyllales, and Boodle (1904) has developed the idea and made it more marked still by the discovery of what he believes to be reduced secondary xylem in the subterranean parts of Psilotum.

There is no need for me to recapitulate here all the details concerned in this double correspondence between the Psilotaceae and the Sphenophyllales, for they have been thoroughly co-ordinated and analysed by most of those who have written recently on the subject, as, e.g., Scott (1909), Sykes (1908), and Boodle (1904).

The peculiar features of the Psilotaceae are open to interpretation in any of the following three ways: They may be regarded as primitive, or as the result of reduction, or as being recent adaptations. This is so also, of course, in other pteridophytic groups, such as, for example, the Lycopodiaceae and the Equisetaceae, and an instructive parallel may be drawn between them and the Psilotaceae in this respect. Through our knowledge of the fossil plants of the Carboniferous and succeeding periods we have learned to look upon each of these two groups as being the modern representatives—mere remnants—of families which dominated the forest of the Palaeozoic age. The modern Lycopods and Equisetums do not show the presence of secondary wood (except in one known instance), and this may indicate either that they have lost it by reduction in their descent from large Carboniferous ancestors which possessed it, or that they are descended rather from humbler ancestors which existed side by side with the tree forms but which had never attained to secondary growth. The comparative study of the stem-stele in the modern Equisetums and the fossil Calamites reveals the presence of a primary structure common to both, so that the modern group in this particular, as also in external form and in the nature of the strobilus, is regarded as preserving primitive characters. The Lycopodiaceae may be read, according to two main

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Corrigendom
Page 40, lines 7–8: For hypobesal read upper.

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theories, either as a reduction series or as a progressive series, the simpler type of Lycopodium, such as L. Selago, being thus regarded either as very much reduced or as primitive in form. Certain features of the embryo and young plant, moreover, peculiar to a section of the Lycopodiaceae have been interpreted as primitive, and primitive not only for the Lycopodiaceae but for vascular plants generally. These are the protocorm and its surmounting protophylls. According to this theory, the protocorm is regarded as an indication of the way in which the primitive sporophyte first became independent of the gametophyte, and in pursuance of this idea the peculiar plant Phylloglossum has been spoken of as the most primitive form of Lycopod. However, a simpler explanation of the protocorm, and one widely accepted, is that it is merely a vegetative adaptation peculiar to one or perhaps two sections of the Lycopodiaceae, and that Phylloglossum has been derived from this particular section by reduction. Again, a third interpretation has been suggested, that the protocorm is a modified form of stem due to reduction, the basis of probability for the truth of this theory being the very large size attained by the Carboniferous ancestors of the Lycopodiums. These varying interpretations of the outstanding features of the Equisetaceae and the Lycopodiaceae are so well known that there is no need for me here to do more than merely indicate them or to cite the authorities. They are mentioned to serve as an analogy to the various interpretations which are possible in the case of the Psilotaceae. It will be necessary for me to discuss briefly the evidence in favour of regarding the Psilotaceae either as reduced forms or as retaining primitive characters.

Boodle (1904, p. 511) interprets the secondary tracheides found by him in certain parts of the stem of Psilotum as reduced secondary xylem, and considers that this feature reinforces the similiarity which has been traced between the Psilotaceae and the Sphenophyllales. He speaks of Psilotum and Tmesipteris as being reduced from “a common parent form, in which the aerial stem had a rayed mesarch xylem mass” (ibid., p. 515) and which also showed secondary thickening. Such a stem, he says, would bear a strong resemblance to the axis of Cheirostrobus; but at the same time he is careful to point out that such a character as the presence of secondary xylem is too adaptive to be taken by itself as evidence of affinity (ibid., p. 513, note 1). However, the presence of secondary xylem in the stem of Psilotum, he says, possesses certain significance in view of the fact that the fertile organ of the Psilotaceae finds its nearest parallel in that of the Sphenophyllales.

There is no doubt that the saprophytic habit of both Psilotum and Tmesipteris, the extreme reduction in the leaves of the former, and the presence in the rhizomes of a mycorhiza, may be taken as suggesting that their present form and structure is, at any rate partly, due to reduction. And, of course, the absence of a root organ may be regarded in the same way. Probably the most interesting point to be elucidated by a study of the life-history of the two members of this class is whether or not there is a rudimentary root organ to be traced in the embryo. Lawson (1917A, p. 793), from his study of the one embryo found by him, concludes that there is such a rudimentary root present. My own study of a number of embryos and of a fairly complete series of young plants has convinced me that there is not, but that the peculiar outgrowth of the absorbing region of the embryo which Lawson speaks of as a rudimentary root is only one of a large number of such outgrowths which are to be regarded

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simply as haustorial protuberances of the surface cells of the foot. If there is no evidence forthcoming that the absence of the root is due to reduction, other than a certain degree of probability arising out of the present habit of the plants, coupled with the fact that in other isolated pteridophytic classes we seem to trace signs of reduction, we must ask, Is there anything to adduce in favour of the theory that the absence of a root in the Psilotaceae is a primitive feature? In this particular character the Psilotaceae stand alone amongst existing Pteridophytes. The fundamental differences between the various classes of Pteridophytes in the manner in which the root is differentiated in the embryo shows that those classes have been distinct from one another from a far-distant period, and accordingly if one of them shows the total absence of a root from its embryo this may quite conceivably be due to the preservation in the one particular line of descent of a primitive character of vascular plants. Such a theory will, of course, best be substantiated by direct evidence from the fossil record. Such evidence has lately been brought forward by Kidston and Lang in their account of the fossil plant Rhynia Gwynne-Vaughani (1917). It must suffice here for me to mention briefly those points in their paper which bear directly upon the present subject. The authors themselves state that they have reserved to a later paper their own discussion of the relation of their plant to the important questions concerning the differentiation of primitive Pteridophytes into stem, root, and leaf (ibid., p. 775).

Rhynia Gwynne-Vaughani occurs in the Old Red Sandstone of Aberdeen, and is, as its investigators point out, “the most ancient land-plant of which the structure is at all fully known.” Fortunately, the plant was preserved in large numbers as it grew, and Kidston and Lang have been able to elucidate fully its general habit of growth, external form, and structure. The plant was leafless and rootless, the branched cylindical stems being differentiated into underground rhizoid-bearing rhizomes and tapering aerial stems. Branching of the stem was by the dichotomous division of its apex, or more frequently by the formation on the stem of adventitious lateral branches. The vascular system of the plant consisted throughout of a simple cylindrical stele composed of a slender solid strand of tracheides, with no distinction of protoxylem and metaxylem, surrounded by a zone of phloem. The possession of these general characters leads Kidston and Lang to compare Rhynia with the existing Psilotales; but the presence of certain other characters, such as the total absence of leaves, the consistent simplicity of the stele, and especially the single large sporangia borne terminally on short stalks, has decided them to recognize a new pteridophytic class (to which they propose to give the name “Psilophytales”) somewhat resembling the modern class Psilotales, and embracing with Rhynia certain Devonian plant fossils. The authors note that the comparison which they institute between Rhynia and the Psilotaceae “would lead us to regard the Psilotaceae as having preserved many primitive characters, and not as reduced. On this view the Psilotaceae would be the little-modified survivors in the existing flora of a type of plant that existed in early geological times, the most fully known example of which is now Rhynia Gwynne-Vaughani. It does not follow, however, that a direct line of descent is to be drawn between Rhynia and the Psilotaceae as we know them” (ibid., p. 776).

It might, of course, with some reason be argued that the simple morphological nature of Rhynia was due to reduction; but, all things considered, it is more likely that the characters of this ancient plant are primitive

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rather than reduced. The account given in the present paper of the life-history of Tmesipteris lends weight to Kidston and Lang's suggestion that the Psilotaceae, on account of their remarkable resemblance to Rhynia, are to be regarded as possessing primitive characters. The structure of the sexual organs, of the embryo, and of the young plant of Tmesipteris confirm the idea that the Psilotaceae should be removed from all other existing classes of Pteridophytes. The structure and form of the prothallus is also peculiar, but probably the gametophyte generation is always too adaptive to form the basis for much generalization. The simple stele found throughout the young plant of Tmesipteris in both rhizome and aerial stem resembles that of the Psilophytales. The theory that the mature plant of the Psilotaceae, as regards both its more complete vascular anatomy and also the nature of its sporophylls, finds in the Sphenophyllales its nearest resemblances is quite compatible with the belief that in other respects the Psilotaceae have preserved the same primitive characters as are exemplified in Rhynia.

Just what is the degree of relationship between the Psilotaceae and these groups of fossil Pteridophytes is still, of course, far from clear. But this much, at any rate, may be said: that we have learned to look for the nearest relationships of this peculiar modern class of plants in the fossil record, just as has been done in the case of the Lycopodiums and Equisetums; and that while undoubtedly certain outstanding characters in the case of each of these modern remnants of once flourishing and important groups are best interpreted as reduced or even as adaptive, others, again, must be regarded as primitive, for they may be directly compared with corresponding characters in fossil plants.

Postscript.

At the same time that the proofs of this paper were returned to me from the printer for a second revision Professor A. A. Lawson's second account of the prothallus of Tmesipteris (Lawson, 1917B) was kindly sent to me by its author, so that I am able to give in the form of an appendix a short comparison of his corrected results with mine.

My own account of the prothallus of Tmesipteris as given above corresponds more closely with that given by Lawson in his second paper than in his first. Since writing his preliminary account Lawson found a large number of prothalli, a certain proportion of which would be more or less complete, at any rate as regards their growing apices. One of these is figured by him (fig. 1). This prothallus shows a close resemblance to those figured in the present paper. Certain differences are due to the fact that Lawson's prothalli occurred terrestrially in a sandy soil, whereas mine were found amongst the tangle of aerial rootlets on tree-fern stems where the humus was scanty. More important differences to be noted are that Lawson does not describe or figure the first-formed tapering region of the prothallus: he describes the branching as irregular, whereas I have shown that it takes place normally according to a regular sequence of dichotomies; and the growing apices of his prothalli are not swollen, as were most of mine; also, my prothalli are stouter and more strongly grown. Otherwise, it seems to be clear from our two accounts that our prothalli are identical in nature. My account of the mature archegonia and antheridia corresponds also with that given by Lawson in his second paper. He there corrects his previous account of the mature archegonium, and shows, as I also have pointed out above, that there is a straight

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projecting neck of four tiers of cells, which in most cases in the mature organ falls off almost level with the surface of the prothallus. In figs. 7 and 8 he shows two stages in the development of the antheridium. He gives no account of the embryo in this second paper, but leaves this subject for a still further communication.

In the same paper Professor Lawson describes and figures the prothallus and sexual organs of Psilotum. Here again his description is based upon ample material. There is no need for me to go into any detail other than to notice that Lawson draws attention to the remarkably close similarity between the prothalli and sexual organs of the two genera. This similarity in the matter of the gametophyte generation bears witness to the very near affinity of Psilotum with Tmesipteris, and serves also to draw our attention to the fact of the essential similarity in the stelar anatomy of the sporophyte. Lawson notes that the prothallus of Psilotum as described by him differs wholly from that which Lang provisionally assigned to Psilotum.

I have not seen Darnell-Smith's paper on the gametophyte of Psilotum (Trans. Roy. Soc. Edin., vol. 52, 1917), quoted by Professor Lawson, in which he gives his observations on the germination of the spore, so cannot compare what he there says concerning the first-formed part of the prothallus with what I have described in the present paper in various well-grown prothalli with regard to the same.

Literature Consulted.

Boodle, L. A., 1904. On the Occurrence of Secondary Xylem in Psilotum, Ann. Bot., vol. 18, pp. 505–17.

Bower, F. O., 1894. Studies in the Morphology of the Spore-producing Members, I. Equiset. and Lycopod., Phil. Trans. Roy. Soc. Lond., ser. B, vol. 186.

—— 1908. The Origin of a Land Flora, London.

Bruchmann, H., 1898. Über die Prothallien und die Keimpflanzen mehrerer europäischer Lycopodien, Gotha.

Campbell, D. H., 1911. The Eusporangiatae—The Comparative Morphology of the Ophioglossaceae and Marattiaceae, Washington.

Cheeseman, T. F., 1906. Manual of the New Zealand Flora, Wellington.

Englerw, A., and Prantl, K., 1900. Pflanzenfamilien, Teil 1, Abteilung iv, Psilotaceae.

Ford, Miss S. O., 1904. The Anatomy of Psilotum triquetrum, Ann. Bot., vol. 18, pp. 589–605.

Kidston, R., and Lang, W. H., 1917. On Old Red Sandstone Plants, showing Structure, from the Rhynie Chert Bed, Aberdeenshire, Pt. i, Rhynia Gwynne-Vaughani, Trans. Roy. Sec. Edin., vol. 51, pt. 3, No. 24.

Lang, W. H., 1902. On the Prothalli of Ophioglossum pendulum and Helminthostachys zeylanica, Ann. Bot., vol. 16, pp. 23–56.

—, W. H., 1904. On a Prothallus provisionally referred to Psilotum, Ann. Bot., vol. 18, pp. 571–77.

Lawson, A. A., 1917A. The Prothallus of Tmesipteris tannensis. Trans. Roy. Soc. Edin., vol. 51, pt. iii, pp. 785–94.

—, A. A., 1917B. The Gametophyte Generation of the Psilotaceae, Trans. Roy. Soc. Edin., vol. 52, pt. i, pp. 93–113.

Scott, D. H., 1909. Studies in Fossil Botany, 2nd ed. (1st ed. 1900), London.

Seward, A. C., 1910. Fossil Plants, vol. 2, Cambridge.

Stkes, Miss M. G., 1908. The Anatomy and Morphology of Tmesipteris, Ann. Bot., vol. 22, pp. 63–89.

Thomas, A. P. W., 1902. The Affinity of Tmesipteris with the Sphenophyllales, Proc. Roy. Soc., vol. 69, pp. 343–50.

Treub, M., 1884–90. Études sur les Lycopodiacées, Ann. du Jard. bot. de Buit. (References in standard works.)

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I.—Miscellaneous.

Art. II.—The Resistance to the Flow of Water through Pipes.

[Read before the Technological Section of the Wellington Philosophical Society, 7th July, 1917; received by Editors, 31st December, 1917; issued separately, 24th May, 1928.]

Introductory.

In a previous contribution to this subject communicated to the Philosophical Society, and printed in the Transactions of the New Zealand Institute,* an attempt was made to determine the limits between which the resistance to the flow of water in a turbulent state is found to vary, first, for riveted steel pipes, and, secondly, for wood-stave pipes. This was done by plotting all the experimental determinations of loss of head which are on record and afterwards enveloping the observations as a whole by curves, the form of which was deduced from analogy with the ascertained law of resistance to flow through smooth pipes. In the present contribution an attempt is made to analyse the effect of different surfaces more in detail and to extend the study of the subject. The principle herein employed has been applied by the author to the observations upon the resistance to the flow of water in open channels, and the results communicated to the New Zealand Society of Civil Engineers.

It is well known that the flow of water or any fluid assumes two different modes, the one in which the flow is linear and known as streamline or viscous motion, and the other in which the flow is non-linear or sinuous, the flow being otherwise described as eddying or turbulent. The two terms “linear” and “sinuous” describe the two states very well, and are used herein in the sense defined. Between the two states there is an unstable region below which the flow is linear and above which it is sinuous.

In the linear stage the between relationship the elements affecting the resistance to motion is simple in character, and in consequence the nature of the relationship was discovered by experiment at an early date and subsequently rationalized, and is expressed as follows:—

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rs/v2 = a (v/vd) (1)

where s is the hydraulic gradient, r the hydraulic mean depth, d the diameter of the pipe, v the mean velocity, v the kinematic viscosity (i.e., the viscosity divided by the density of the fluid), and a a constant. Here the resistance is expressed as a loss of head per unit length of pipe, as is customary in engineering practice, whilst the customary notation has also been adopted—viz., r and s for the hydraulic mean depth and hydraulic gradient respectively.

In the sinuous or eddying stage, on the other hand, the relation between the elements of resistance is evidently complex, and as a

[Footnote] * E. Parry, Resistance to the Flow of Fluids through Pipes, Trans. N.Z. Inst., vol 48, pp. 481–89, 1916.

[Footnote] † E Parry, A Critical Discussion of the Subject of the Flow of Water in Pipes and Channels, with Special Reference to the Latter, Proc. N.Z. Soc. Civil Engineers, vol. 3, pp. 116–32, 1917.

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consequence the efforts of experimenters to discover the nature of the relationship has been fruitless, and, as little or nothing is known of the transformation of energy within fluids in sinuous motion, a precise mathematical solution was impossible. It may, however, be deduced from certain dynamical principles that the resistance is some function of (v/vd) provided that there is a proportionality between the dimensions of the eddies and of the cross-section of the pipe, leaving the form of the function to be determined by experiment.

The law of resistance, then, in its most general form, which applies to both states of motion, is expressed as follows:—

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rs/v2 = φ (v/vd) (2) where φ stands for “function of” and the other symbols have the same significance as in equation (1). As already explained, the relation between the quantities in the linear state is a simple one, the left-hand expression in equation (2) being a simple linear function of the right hand.

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As regards sinuous or turbulent flow, it was supposed at one time that the nature of the function was of the form rs/v2 = a (v vd)n (3) but it is now known that this form is defective, and that the range of observations upon which it was based was not wide enough to determine the true form; it was soon found that equation (3) did not fit the facts, and in consequence a modification of this was adopted in which v was treated as a constant, and independent indices given to v and d, yielding a formula of the form v = krxsy(4) where k, x are constants and r is the hydraulic mean depth numerically equal to d/4 for round pipe.

This formula is one of considerable flexibility, and of late the whole phenomenon of the flow of water in pipes has been analysed afresh and expressed in the form given in equation (4). Its adoption has not, however, contributed anything towards extending our knowledge of the subject, and it is much to be regretted that steps were not taken to extend the range of observations when equation (3) was found to be defective. This aspect of the question has been apparently overlooked.

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Such a series of observations extending over a wide range was recently conducted in the National Physical Laboratory by Stanton and Pannell* upon oil, air, and water in smooth brass pipes. The diameters of the pipes used varied from 0 142 in. to 5 in., and the mean speed from a fraction of a foot to 20 ft. per second. These combined with other observations upon the flow of water in smooth pipes when plotted with rs/v2 as ordinates and log. vd/v as abscissae were found to be sufficiently near to enable a curve to be drawn through the mean which was fairly representative of the whole, despite the fact that the condition of geometric similarity was not observed in respect to the surface of the

[Footnote] * T. E. Stanton and I. R. Pannell, Similarity of Motion in Relation to the Surface Friction of Fluids, Phil. Trans Roy. Soc., A, vol. 214, pp. 199–224, 1914.

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pipes. According to Professor Lees,* the mean curve can be expressed in the form rs/v2 = a (v/vd)n + b (5) the values, the coefficients, and the index being as follows:— a = 0.00801; b = 0.000028; n = 0.35 all the quantities being in foot-pound units.

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More recently Lander carried out an extensive series of experiments upon the flow of water and steam at speeds varying from 1.91 ft. per second to 11.55 ft. per second through ordinary commercial drawn-steel pipe of 0.423 in. diameter, and upon plotting the values of rs/v2 against log. vd/v he finds than an equation of the form (5) satisfies the relation between them. He, however, obtains different values of the coefficient and of the indices, the values being a = 0.0202; b = 0.0000622; n = 0.44 all values being in foot-pound units.

It is evident on contemplating the two sets of experiments that an equation of the form given in (5) correctly expresses the relation between the quantities near enough for all practical purposes, and it remains to be seen how far the principle is applicable to larger diameters and rougher surfaces, and it is the purpose of this paper to test its applicability to cast-iron, riveted steel, and wood-stave pipes of such sizes and characteristics as are in common use in the arts.

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Before proceeding further in the direction indicated it may be useful and interesting to compare the form of equation (5) with Chezy's formula, viz.:— v = crs (6) where c is a coefficient and r the hyraulic mean depth. It will be seen that c can be expressed in the form c = 1/√ a (v/vd)n + b (7) Comparing this with other well-known formulae for c, we have Prony's equation, viz.:— c = 1/√ a (1/v) + b (7) whilst Darcy and Bazm's formula may be expressed as follows:— c = 1/√a(1/d). + b Evidently the influence and value of v predominate in Prony's experiments, whilst the value of d predominated in Darcy's experiments; and

[Footnote] * C. H. Lees, On the Flow of Viscous Fluids through Smooth Circular Pipes, Proc. Roy. Soc., A, vol. 91, pp. 46–53, 1914.

[Footnote] † C. H. Lander, Surface Friction: Experiments with Steam and Water in Pipes, Proc. Roy. Soc., A, vol. 92, pp. 337–53, 1916.

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it does not seem to have occurred to any one to combine the two and thereby obtain an approximation to equation (7).

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Kutter's formula for c is too complicated for ready comparison, and, after all, what is required is not a formula for c, but a sufficient number of observations for each class of pipe to enable a curve to be drawn correlating rs/v2 to vd/v. The precise form of the equation expressing the relationship is really only of academic interest.

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Returning to equation (5), the results of the experiments on smooth pipe by Stanton and Pannell are plotted in figs. 1, 2, and 3, and indicated by the number 6, whilst the result of Lander's experiments on drawnsteel pipe is indicated by the number 10, the abscissae being values of log. vd/v and the ordinates values of rs/v2. In fig. 4 the same equations are plotted in terms of log. (rs/v2b) and log. vd/v.. Line 6 represents Stanton's experiments, and line 10 Lander's. These two lines converge at or near to a point 0, where the motion changes from linear to sinuous. Line 12 represents linear flow, and should be common to all pipes within limits. The convergence of these three lines indicates that the two pipes fulfil the condition as regards geometric similarity. The method of plotting adopted in fig. 4 affords a ready means of determining the characteristic of any description of surface, provided that the condition before mentioned is fulfilled, for it is only necessary to make one observation of the quantities involved and to join the point representing the observed value to the point 0 in order to determine the whole characteristic. There is one remarkable coincidence between Stanton's and Lander's results—viz., the ratio of a to b is the same in both; which suggests a possible relationship which would be most useful if it can be proved to have any dynamical significance, but no deduction can be made in the absence of such a proof.

In applying the principle involved in equation (2) to experiments upon large pipes we encounter several elements of uncertainty. One is that the temperature of the water has not, as a rule, been observed and recorded; but as the error involved in assuming a uniform temperature and applying it to all the experiments is considerably less than the error arising out of other disturbing factors, and probably less than the error of observation under the conditions prevailing during the experiments, the temperature error is of no great moment.

Another factor which affects the harmony of the results arises from the fact that large-diameter pipe lengths are shorter than small-diameter pipes, and that in consequence the joints are more frequent; and, as the joint is a disturbing element, a large pipe and a small pipe of the same material and surface—such, for instance, as cast iron—are not strictly comparable on account of the increase in the number of joints, and often also because of the different nature of the joint. There is also the possibility that in two experiments on pipes of the same size and material the joint of the one may be better made than that of the other, and greater care taken in aligning the pipes.

In the case of riveted steel pipes we have still other disturbing factors. The longitudinal joints may be lapped or butted. There may be one, two, or three longitudinal joints in the circumference The circumferential joints may be alternately in and out, or taper; in neither case is the diameter of the pipe uniform. In one case we have a larger diameter alternating with a smaller diameter by twice the thickness of metal, with

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the plate at the joint alternately facing and not facing the stream; in the other case we have the plate or section tapering from a large end to a small end by twice the thickness of the plate, whilst none of the joints face the stream. There is further the disturbance arising out of the different thickness of plate used, and in comparing two riveted pipes of different diameter it will be realized that they are not similar in all respects unless the thickness of plate bears some proportion to the diameter. The same remarks apply generally to spirally riveted pipe.

The principle involved demands that for the same values of vd at the same temperature the same value of rs/v2 shall be obtained; but unless the frequency of jointing and the nature of the joints is the same, and unless there is a proportionality between diameter, thickness of plate, and size of rivet, it cannot be expected that the principle can be strictly applied, or that it can be proved to be applicable at all unless the characteristics mentioned are taken into account.

In spite of the vast array of experiments upon pipes of different kinds, it will be found that few of them are of much assistance in the present investigation. The characteristics of the pipe are not always precisely defined. The experiments on any one set are usually not numerous enough, or, if numerous, do not cover a sufficient range. Those experiments that are at all suitable have been used in the present paper, and a study of the diagrams will afford an indication as to the scope which should be given to further experiments.

In addition to the disturbing factors arising out of the nature of the surface, and frequency and nature of the joints, the thickness of plate in riveted pipe, and riveting, there is evidently another disturbing element arising out of the elastic compression of the water and from the acceleration and retardation of the flow. Most of the available observations on large pipe have been obtained under working conditions, and subject to disturbances arising out of change in velocity of flow due to the operation of valves and governors. When a change in velocity of flow is made, a wave of alternate compression and expansion is set up which takes some time to die down, especially if the pipe is a long one, and it is quite possible to obtain widely conflicting results on the same pipe and for the same average flow, due to the operation of the various impulses that may be set up. Another possible source of irregularity is the occlusion of air in larger or smaller quantities due to fluctuations of pressure. This might affect the flow considerably at a given head, whilst the proximity of the gauge to a bend or to a discharge-opening has been found to vitiate the results. That some disturbances of the kind mentioned are at work will be quite evident on contemplating the graphs showing the results, to which attention will now be drawn.

Cast-iron Pipe.

A very complete list of experiments on loss of head in cast-iron pipe will be found in Barnes's work, Hydraulic Flow Reviewed, including some particularly careful determinations by the said author himself, which fulfil all the requirements. The examples selected are taken from the publication mentioned. Four experiments by Darcy on clean, new, uncoated cast-iron pipes are represented by a, b, c, and k in fig. 1, the diameters varying from 0.2678 ft. to 1.6404 ft. The readings are erratic, and no conclusion can be drawn from them further than that the trend of the observations generally follows the curve for drawn-steel pipes. The remaining experiments are upon asphalted cast-iron pipes, either

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Fig.1. Transactions.

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Fig. 2.

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newly cleaned or new. The diameters vary from 3.333 ft. to 5.0938 ft. by four different observers and six sets of observations. All the readings are remarkably close, and form a most valuable groundwork for further investigation. There are in all forty-six observations, all within the limit of observational errors, which could be represented by a single curve. All that is required in regard to this class of surface is a number of observations between the values of log. vd/v = 6 and log. vd/v = 7. Even as they stand a curve could be drawn with a fair amount of probability as to its correctness, as the observations follow the curve for brass tube; but, as the determination of the function is essentially an experimental one, the completion of the curve should be left to experiment.

Wood-stave Pipe.

Among the available experiments on wood-stave pipe, the most complete are those by Moritz.* Two classes of pipe are used—viz., jointed and continuous. The frequency of joints in the former case is, however, not specified. The observations on 18 in., 14 in., 12 in., 8 in. jointed pipe, and on a 55 ¾ in. by Moritz, and a 31 in. continuous by Moore, are plotted in fig. 2. It will be seen that in spite of the care exercised the results obtained on some of the pipes are somewhat erratic, due, no doubt, to the effect of impulses travelling through the water. The results as a whole are not consistent, and they do not lie near enough together to enable them to be represented to a single line, as the underlying principle demands. Nevertheless, they do not disprove the applicability of the principle, as the results are not consistent, whilst the difference between the observations on the same pipe are greater than the differences between the different pipes.

Riveted Steel Pipe.

Of the numerous experiments on riveted steel pipe, but two or three are suitable for the purpose of this paper. As a rule, the range is short and the readings erratic, whilst the particulars of the pipe are not complete. One of the most complete and extensive sets of observations is that made by Marx, Wing, and Hoskins upon a pipe 6 04 ft. in diameter, the circular joints being butted, with a strap on the outside. The longitudinal joints are also butted, with a strap both inside and out. The length of pipe was 4,427 ft., with fourteen joints, and contained thirteen bends of 30 ft. radius and one of 40 ft. radius. The temperature of water is also recorded. The results are plotted in fig. 3 and marked a. On the same diagram are plotted experimental values by Herschell on a 48 in. pipe marked b and a 36 in. pipe marked c. In each case the plates are ¼ in. thick and asphalted, built with alternate large and small cross-sections. All three sets of results are erratic, giving widely different values of 1/c2 for the same value of vd/v, and the readings on the same pipe differ more than the difference between the pipes, so that no conclusion can be drawn as to the complete applicability of the principle involved. All that can be

[Footnote] * E. A. Moritz, Experiments on the Flow of Water in Wood stave Pipes, Trans. Am. Soc. Civ. Eng, vol. 74, pp. 411–51, 1911.

[Footnote] † C. D. Marx, C. B. Wing, and L. M. Hoskins, Experiments on the Flow of Water in the Six-foot Steel and Wood Pipe Line of the Pioneer Electric Power Company at Ogden, Utah, Second Series, Trans. Am. Soc. Civ. Eng., vol. 44, pp. 34–54, 1900.

[Footnote] ‡ One Hundred and Fifteen Experiments on the Carrying-capacity of Large Riveted Metal Conduits, John Wiley and Sons, N.Y.

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Fig. 3.

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Fig. 4.

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gathered from contemplating them is that their general trend indicates that the law of resistance can be expressed in the form of equation (5). The observations are, however, not consistent enough among themselves, and, if they were, they do not cover a sufficiently wide range to enable a curve expressing the relation between rs/v2 and vd/v to be drawn. There is evidently some disturbing factor at work which seems to have a greater effect at low values of the mean velocity and low friction heads.

Comparisions.

Comparing the results as a whole as plotted in figs. 1, 2, and 3, it may be said that their general trend is such as to conform with the law expressed in equation (5), and that they do not disprove the wide application of the principle to comprehend both large and small diameters, provided that the surface characteristics are similar.

As regards cast iron with clean, asphalted surfaces, the results of the more recent experiments are remarkably consistent and afford strong evidence in support of the theory, and it only requires a few more experiments in the proper region of exploration in order to enable a curve to be drawn for this class of surface.

As regards wood-stave pipe, the available results are not consistent, and new observations are required throughout the range.

As regards riveted steel pipes, none of the existing data are of much assistance, because of the wide variations between the readings. It is evident that in all the experiments some disturbing factors were operating in such a way as to vitiate the results, these making their influence felt more at low than at high velocities. More experiments extending over a wider range are required.

Conclusion.

The result of this investigation is not very conclusive. A beginning is, however, made in the direction of applying a principle which has been found to be applicable throughout a wide range of values of vd, and for widely different fluids, such as water, air, and steam, and extending it to large pipes in commercial use; and before further progress can be made more experiments are required on pipes of different diameters and different surface characteristics, selected with a view to extending the range of observations already obtained.

Whether or not this theory is applicable under all conditions, there is considerable advantage to be derived from plotting the results of observations against vd/v, as by this means one is able to exercise a far greater degree of judgment in selecting a probable value of c than by studying all the literature on the subject which exists, and the method is to be recommended on this account.

Readers are referred to a previous paper,* printed in the Transactions of the New Zealand Institute, for a diagram representing the coefficient of viscosity and the coefficient of kinematic viscosity of water at different temperatures, and also a diagram showing the relation between the values of log. vd/v and vd for water at temperatures 0, 10, 20, and 30 degrees centigrade, the use of which will facilitate the manipulation of the diagrams presented in this paper.

[Footnote] * E. Parry, Resistance to the Flow of Fluids through Pipes, Trans. N.Z. Inst., vol. 48, pp 487–88, 1916.

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Art. III.—Revision of the Cirripedia of New Zealand.

Communicated by Dr. Charles Chilton.

[Read before the Philosophical Institute of Canterbury, 5th December, 1917; received by Editors, 31st December, 1917; issued separately, 24tth May, 1918.]

Introductory Note.

The late Captain L. S. Jennings commenced the study of the New Zealand Cirripedia, a group of animals that had received very little attention from local naturalists, in 1910, and, becoming greatly interested in the subject, he continued his observations with much enthusiasm and great thoroughness, and hoped to be able to prepare a comprehensive paper dealing with the whole group. In 1915 he published a paper on the “Pedunculate Cirripedia of New Zealand and Neighbouring Islands” (Trans. N.Z. Inst., vol. 47, p. 285). In this he gave a revised list of the species known to occur in the New Zealand region, established a new variety of Lepas anatifera Linn., and gave a critical discussion of the specific characters of Lepas anatifera Linn. and of the New Zealand species Pollicipes. He had nearly completed his examination of the sessile Cirripedia when he left for the front, and before his departure he gave into my charge all his specimens and manuscript notes. Though nearly all the essential work of identifying the species had been done, the manuscript was not arranged in a form suitable for publication. Mrs. Jennings has carefully gone over the collection, under my supervision, and has put the notes in order for publication. The paper contains a list of the New Zealand species examined by Captain Jennings, with localities, & c., of the different species.

References have been added to Pilsbry's “Sessile Barnacles (Cirripedia) contained in the Collections of the U.S. National Museum” (1916*), and to Borradaile's “Report on the Cirripedia of the ‘Terra Nova’ Antarctic Expedition” (1916 and 1917)—works which Captain Jennings had no opportunity of seeing.

In the list given below only those species are included which had been examined by Captain Jennings. Additional species are recorded from New Zealand by Hutton (1879, p. 330), Filhol (1885, p. 485), and Borradaile (1916, p. 128).

Those references only have been given which appear necessary for New Zealand workers.

The collection has been named and arranged in order, and is stored in the Biological Laboratory of Canterbury College. It contains a few specimens added after Captain Jennings left New Zealand, mainly from the collections of Mr. W. R. B. Oliver.

Captain Jennings was killed in action in France on the 15th September, 1916. By his death New Zealand was deprived of one of the most promising of the younger generation of workers in science.

Chas. Chilton

[Footnote] * The references are made by the year of publication to the bibliographical list on p. 63

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Family Lepadidae.

Lepas anatifera Linnaeus.

Lepas anatifera Linnaeus, 1758, Systema Naturae, 10th ed., p. 668; Darwin, 1851, p. 73; Gruvel, 1905, p. 108; Pilsbry, 1907, p. 79; Chilton, 1911A, p. 571; L. S. Jennings, 1915, pp. 285, 288, figs. 1 (a, b, c), 2.

Specific Diagnosis.—“Valves smooth, or delicately striated. Right-hand scutum alone furnished with internal umbonal tooth: uppermost part of peduncle dark-coloured. Filaments, two on each side.” (Darwin.)

Var. (a). “Scuta and terga with one or more diagonal lines of dark greenish-brown, square, slightly depressed marks.” (Darwin.)

Var. (b). “Carina strongly barbed.” (Darwin.)

Var. (c).* “No trace of an umbonal tooth on either scutum. The carina is not barbed and square patches on the capitulum are not visible.” (Jennings.)

Localities.—General type: Sunday Island, Kermadecs (Bell and W. R. B. Oliver). Locality unknown—Specimens in Canterbury Museum.

Var. (b): Sunday Island, Kermadecs (W. R. B. Oliver).

Var. (c): Chatham Islands (Miss S. D. Shand); hull of “Terra Nova,” Lyttelton (C. Chilton); Waitakerei River, washed up on beach (W. R. B. Oliver).

Lepas hillii Leach.

Pentalasmis hillii Leach, 1818, Tuckey's Congo Exped., p. 413. Lepas hillii Darwin, 1851, p. 77, pl. i, fig. 2; Gruvel, 1905, p. 110, figs. 124, 125; Pilsbry, 1907, p. 80, pl. viii, figs. 2, 7; Jennings, 1915, p. 287.

Specific Diagnosis.—“Valves smooth: scuta destitute of internal umbonal teeth; carina standing a little separate from the other valves, with the fork not close to the basal margin of the scuta; uppermost part of the peduncle either pale or orange coloured. Filaments three on each side.” (Darwin.)

Locality.—Hull of “Terra Nova,” Lyttelton Harbour (C. Chilton).

Lepas pectinata Spengler.

Lepas pectinata Spengler, 1793, Skrifter Naturhist. Selbskabet, 2 B., 2 H., Tab. x, fig. 2; Darwin, 1851, p. 85, pl. i, figs. 3, 3a; Hutton, 1878, p. 329; Gruvel, 1905, p. 107, fig. 119; Pilsbry, 1907, p. 81, pl. viii, figs. 4–8; Chilton, 1911A, p. 571; Jennings, 1915, p. 286; Borradaile, 1916, p. 131.

Specific Diagnosis.—“Valves thin, coarsely furrowed, often pectinated. Scuta with a prominent ridge extending, from the umbo to the apex, close to the occludent margin; fork of the carina with the prongs diverging at an angle of from 135° to 180°. Filaments absent, or only one on each side.” (Darwin.)

Var. (a). “Upper part of the terga (bounded by the two occludent margins) produced and sharp; surface of all the valves often coarsely, pectinated, and with the carina barbed.” (Darwin:)

[Footnote] * This variety has been described as a new species by Borradaile, under the name L. affinis (see Borradaile, 1916, p. 131, and 1917, p. 229).—C. C.

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Localities.—General type: Chatham Islands (A. Dendy).

Var. (a): Kermadec Islands (W. R. B. Oliver); Waitakerei River, washed up on beach (W. R. B. Oliver); off Three Kings Islands (L. A Borradaile).

Lepas australis Darwin.

Lepas australis Darwin, 1851, p. 89, pl. i, fig. 5; Hutton, 1879, p. 329; Gruvel, 1905, p. 109, fig. 122; L. S. Jennings, 1915, p. 285.

Specific Diagnosis.—“Valves smooth, thin, brittle; scuta with internal umbonal teeth on both sides. Carina with upper part broad, flat; much constricted above the fork, which has wide, flat, thin, pointed prongs, with the intermediate rim not reflexed. Filaments two on each side.” (Darwin.)

Localities.—New Plymouth beach (Mrs. B. D. Jennings); Sumner (A. F. Barrell); New Brighton (G. E. Archey and L. S. Jennings); hull of “Terra Nova,” Lyttelton Harbour (C. Chilton); Cape Campbell (T McAlpine).

Lepas fascicularis Ellis and Solander.

Lepas fascicularis Ellis and Solander, 1786, Zoophytes, Tab. xv, fig. 5; Darwin, 1851, p. 92, pl. i, fig. 6; Hutton, 1879, p. 329; Gruvel, 1905, p. 105, fig. 116; Pilsbry, 1907, p. 81, pl. ix, fig. 6; Chilton, 1911A, p. 572; Jennings, 1915, p. 286.

Specific Diagnosis.—“Valves smooth, thin, transparent; carina rectangularly bent, with the lower part expanded into a flat oblong disc. Filaments, five on each side; segments of the three posterior cirri with triangular brushes of spines.” (Darwin.)

Localities.—New Brighton (A. Dendy); Sunday Island, Kermadecs (W. R. B. Oliver); Waitakerei River, washed up on beach (W. R. B. Oliver).

Lepas denticulata Gruvel, 1900.

Lepas denticulata Gruvel, 1905, p. 106, fig. 118; Chilton, 1911A, p. 571; Jennings, 1915, p. 286.

Specific Diagnosis.—“Capitulum avec cinq plaques tres serrées, de couleur très blanche et fortement pectinées. Carène terminée en fourche è sa partie inférieure, chacune des branches portant, du côté pédonculaire, deux pointes saillantes, l'interne plus longue que l'externe; crĉte médiane dorsale avex quatre fortes dents et une série de plus petites entre les premières. Bord occluseur des scuta, convexe et fortement saillant antérieurement. Une dent è l'angle umbonal interne du scutum gauche. Rien è droite. Pas d'appendices filamenteux.” (Gruvel.)

Locality.—Kermadecs (Captain Bollons, 1907).

Conchoderma auritum (Linnaeus).

Lepas aurita Linnaeus, 1767, Systema Naturae, ed. 12, p. 1110. Conchoderma aurita Darwin, 1851, p. 141, pl. iii, fig. 4; Chilton, 1911c, p. 132; Jennings, 1915, p. 287. Conchoderma auritum, Gruvel, 1905, p. 144, fig. 167; Pilsbry, 1907, p. 99, pl. ix, fig. 2; Pilsbry, 1909, p. 71, pl. viii, figs. 5, 6, 7; Borradaile, 1916, p. 132, and 1917, p. 230.

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Specific Diagnosis.—“Capitulum with two tubular ear-like appendages, seated behind the rudimentary and often absent terga; scuta bilobed.; carina absent, or quite rudimentary; peduncle long, distinctly separated from the capitulum.” (Darwin.)

Localities.—Hull of “Terra Nova,” Lyttelton (C. Chilton); from Megaptera nodosa in the Bay of Islands and off Cape Brett (L. A. Borradaile); on whales (specimens in Otago and Auckland Museums).

Conchoderma virgatum (Spengler).

Lepas virgata Spengler, 1790, Skrifter Naturhist. Selbskabet, B. 1, Tab. vi, fig. 9. Conchoderma virgata Darwin, 1851, p. 146, pl. iii, fig. 2; pl. ix, fig. 4: Chilton, 1911c, p. 132: Jennings, 1915, p. 287. Conchoderma virgatum Gruvel, 1905, p. 144, fig. 168; Pilsbry, 1907, p. 99, pl. ix, fig. 1; Borradaile, 1917, p. 230.

Specific Diagnosis.— “Scuta three-lobed: terga concave internally, with their apices slightly curved inwards: carina moderately developed, slightly curved: peduncle blending into the capitulum.” (Darwin.)

Localities.—Hull of “Terra Nova,” Lyttelton Harbour (C. Chilton); ship's hull, Dunedin (specimens in Otago Museum).

Scalpellum villosum (Leach).

Scalpellum villosum Leach, 1824, Encyclop. Brit. Suppl., vol. iii, pl. lvii; Darwin, 1851, p. 274, pl. vi, fig. 8; Hutton, 1879, p. 329; Gruvel, 1905, p. 33, fig. 32; Pilsbry, 1907, p. 9; Jennings, 1915, p. 286.

Specific Diagnosis.—“Capitulum with fourteen valves: sub-rostrum present: carina nearly straight: three pair of latera; upper latera triangular. Mandibles with four teeth, of which the second is the smallest: maxillae with a projection near the inferior angle: no caudal appendage.

“Complemental male attached externally between the scuta, below the adductor muscle; pedunculated; capitulum formed of six valves, with the carina not descending much below the basal angles of the terga: mouth and cirri prehensile.” (Darwin.)

Localities.—Stewart Island (W. R. B. Oliver); Port Robinson (J. R. Wilkinson); Godley Head (W. R. B. Oliver); Cheltenham Beach, Auckland (W. R. B. Oliver); Oamaru (L. S. Jennings).

Scalpellum spinosum Annandale.

Scalpellum spinosum Annandale, 1911, p. 164, figs. 1–4; Chilton, 1911B, p. 311; Jennings, 1915, p. 286.

Specific Diagnosis.—Capitulum broad, fifteen smooth pinkish valves present, covered with a minutely hairy translucent brownish membrane. Terga large, lozenge-shaped; scuta broadly triangular. Carina short, nearly straight, ridged dorsally but not laterally. Upper latera narrowly triangular. Rostrum, latera of the basal whorl, and subcarina prominent, pointed, spine-like. (Abridged from Annandale.)

Localities.—Farewell Spit, Nelson (W. B. Benham); “Nora Niven” Expedition, Station 5, off Stewart Island.

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Pollicipes* spinosus (Quoy and Gaimard)

Anatifa spinosa Quoy and Gaimard, Voyage de l'Astrolabe, pl. xciii, fig. 17. Pollicipes spinosus Darwin, 1851, p. 324, pl. vii, fig. 4; Hutton, 1879, p. 329; Gruvel, 1905, p. 20, fig. 24; Jennings, 1915, pp. 286, 291, figs. 3a, 3b. Pollicipes sertus Darwin, 1851, p. 327, pl. vii, fig. 5; Gruvel, 1905, p. 22, fig. 25; Jennings, 1915, pp. 286, 291. Pollicipes darwini Hutton, 1879, p. 329; Gruvel, 1905, p. 21; Jennings, 1915, pp. 286, 291.

Specific Diagnosis.—“Capitulum with one or more whorls of valves under the rostrum: upper pair of latera only slightly larger than lower latera: membrane covering the valves (when dried) light yellowish-brown: scales of the peduncle of unequal sizes, unsymmetrical, arranged in rather distant whorls.” (Darwin.)

Localities.—Kaikoura (collector unknown); Port Pegasus, Stewart Island (collector unknown); Russell, Bay of Islands (W. R. B. Oliver); Tauranga (W. R. B. Oliver); Godley Heads (W. R. B. Oliver); Stewart Island (W. Traill); Kaikoura (L. S. Jennings); Oamaru (L. S. Jennings); St. Clair, Dunedin (L. S. Jennings); Taylor's Mistake, Banks Peninsula (L. S. Jennings).

The reasons for considering P. sertus Darwin and P. darwini Hutton to be synonyms of P. spinosus Quoy and Gaimard have already been fully discussed. (See Trans. N.Z. Inst., vol. 47, p. 291, 1915.)

Family Balanidae.

Balanus tintinnabulum (Linnaeus).

Lepas tintinnabulum Linnaeus, 1758, Systema Naturae, ed. 10, p. 668. Balanus tintinnabulum Darwin, 1854, p. 194, pl. i, figs. a-l; pl. ii, figs. 1a-1o: Gruvel, 1905, p. 211, figs. 230–33: Pilsbry, 1916, p. 54.

Specific Diagnosis.—“Shell varying from pink to blackish-purple, often striped and ribbed longitudinally: orifice generally entire, sometimes toothed. Scutum with the articular ridge broad and reflexed. Tergum with the basal margin generally forming a straight line on opposite sides of the spur.”

“Var. (8) concinnus: Globulo-conical; walls finely ribbed: dull purple, tinged and freckled with white; scutum, with a broad, hooked, articular ridge, with an extremely sharp plate-like adductor ridge, and with a cavity, bordered by a plate, for the rostral depressor muscle.” (Darwin.)

Locality.—Hull of “Terra Nova,” Lyttelton Harbour (C. Chilton).

Balanus decorus Darwin.

Balanus decorus Darwin, 1854, p. 212, pl. 2, figs. 6a, 6b; Gruvel, 1905, p. 214; Chilton, 1909, p. 670, and 1911, p. 311, pl. 58, figs. 1–3; Pilsbry, 1916, pp. 53, 77.

Specific Diagnosis.—“Parietes pale pink; radii rather darker. Scutum with a small articular ridge. Tergum with longitudinal furrow very shallow and open; basal margin on both sides sloping towards the spur.” (Darwin.)

Localities.—British Museum, from New Zealand (type); New Brighton

[Footnote] * In accordance with the rules of priority, Pilsbry uses the generic name Mitella in place of Pollicipes (see Pilsbry, 1907, p. 4, and 1911, p. 33).—C. C.

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Beach (L. S. Jennings); Wanganui (S. H. Drew); Chatham Islands (Dr. E. Kershner); Auckland Islands (C. Chilton).

By the “Nora Niven” Trawling Expedition this species was taken at several localities on the New Zealand coast, many of them growing on the carapace of Paramithrax longicornis Thomson, with which crab the cirripede seems to be specially associated.

Balanus trigonus Darwin.

Balanus trigonus Darwin, 1854, p. 223, pl. 3, figs. 7a-7f Hutton, 1879, p. 330; Gruvel, 1905, p. 223, figs. 248, 249; Pilsbry, 1916, p. 111, pl. 26, figs. 1–13e.

Specific Diagnosis.—“Parietes ribbed, mottled purplish-red; orifice broad, trigonal, hardly toothed. Scutum thick, with from one to six longitudinal rows of little pits. Tergum without a longitudinal furrow; spur truncated, fully one-third of width of valve.” (Darwin.)

Locality.—Rangitoto Reef, Auckland Harbour (W. R. B. Oliver).

Balanus porcatus Da Costa.*

Balanus porcatus Da Costa, 1778, Hist. Nat. Test. Brit., p. 249; Darwin, 1854, p. 256, pl. 6, figs. 4a-4e; Filhol, 1885, p. 487; Gruvel, 1905, p. 237, fig. 264. Balanus balanus Pilsbry, 1916, p. 149.

Specific Diagnosis.—“Shell white, generally sharply ribbed longitudinally: radii with their summits almost parallel to the basis. Scutum longitudinally striated: tergum with the apex produced and purple.” (Darwin.)

Localities.—Auckland (H. Suter); New Zealand (locality not stated) (W. R. B. Oliver).

Balanus crenatus Bruguière.

Belanus crenatus Bruguiére, 1789, Encyclop. méthod. (des Vers), p. 168; Darwin, 1854, p. 261, pl. vi, figs. 6a-6g; Gruvel, 1905, p. 240, figs. 268, 269; Pilsbry, 1916, p. 165, pls. 39, 40.

Specific Diagnosis.—“Shell white: radii with their oblique summits rough and straight. Scutum without an adductor ridge: tergum with spur rounded.” (Darwin.)

Localities.—Hull of “Terra Nova,” Lyttelton Harbour (C. Chilton).

Pilsbry (1916) distinguishes several varieties of this species.

Tetraclita purpurascens (Wood).

Lepas purpurascens Wood, 1815, General Conchology, p. 55, pl. 9, fig. 42. Tetraclita purpurascens Darwin, 1854, p. 337, pl. xi, figs. 1a-1d; Hutton, 1879, p. 328; Gruvel, 1905, p. 285, fig. 308a; Pilsbry, 1916, p. 249.

Specific Diagnosis.—“Shell depressed, pale purple or dirty-white, with the surface longitudinally ribbed, or corroded and granulated: radii or even sutures none, or radii well developed and broad, with summits parallel to

[Footnote] * According to the rules of priority, this species should be named Balanus balanus (Linnaeus), the name adopted by Pilsbry in 1916. For convenience of reference to papers dealing with New Zealand Cirripedia the name used by Jennings in his manuscript notes has been allowed to stand in the text.—C. C.

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the basis: basis membranous: scutum transversely elongated: tergum small, with the spur extremely short and rounded.” (Darwin.)

Locality.—Otago (W. R. B. Oliver).

Elminius modestus Darwin.

Elminius modestus Darwin, 1854, p. 350, pl. 12, figs. 1a-1e; Hutton, 1879, p. 328; Gruvel, 1905, p. 296, figs. 319–322; Pilsbry, 1916, p. 261. Elminius sinuatus Hutton, 1879, p. 328; Gruvel, 1905, p. 295.

Specific Diagnosis.—“Shell folded longitudinally, greenish or white: radii of moderate breadth, smooth-edged: scutum without adductor ridge: tergum narrow, with the spur confluent with basi-scutal angle.” (Darwin.)

Localities.—Lyttelton Harbour (L. S. Jennings); Riwaka, Nelson Harbour (L. S. Jennings); Takapuna Beach; Half-moon Bay, Stewart Island (W. R. B. Oliver); Ponui Island, Hauraki Gulf (C. Chilton).

E. sinuatus Hutton is probably only a variety of E. modestus Darwin. In groups of E. modestus many young specimens have parieties of each valve with two rounded folds, referred to by Hutton in his description of E. sinuatus. The two distinct folds show also when specimens are not crowded together.

Elminius plicatus Gray.

Elminius plicatus Gray, 1843, Appendix to Dieffenbach's Travels in New Zealand, p. 269; Darwin, 1854, p. 351, pl. 12, figs. 2a-2f; Hutton, 1879, p. 328; Gruvel, 1905, p. 296, figs. 318, 321; Pilsbry, 1907, p. 261.

Specific Diagnosis. —“Shell deeply folded longitudinally, corroded, coloured in parts orange: radii very narrow, with their edges sinuous, and slightly dentated: scutum having an adductor ridge.” (Darwin.)

The valves show many variations in elongation of terga, prominence of grooves and ridges, straightness of tergal articular ridge, length and inflexion of tergal furrow, bluntness or beaked nature of apex.

The general appearance of the shell is also extremely variable. When very corroded the walls are extremely thick, by the inward production of the internal ridges, giving an appearance of porosity. These specimens are usually depressed, and are of a grey or dirty-white colour.

Localities.—Kaipara Harbour (Spencer); Shag Point, Otago (W. R. B. Oliver); Lyttelton Harbour (L. S. Jennings); Puhoi Beacon, Auckland Harbour (C. Chilton); Hawera (L. S. Jennings); Ponm Island, Hauraki Gulf (C. Chilton); Oamaru (L. S. Jennings); Takapuna, Auckland (W. R. B. Oliver).

Coronula diadema (Linnaeus).

Lepas diadema Linnaeus, 1767, Systema Naturae, ed. 12, p. 1109. Coronula diadema Darwin, 1854, p. 417, pl. xv, figs. 3, 3a, 3b; pl. xvi, figs. 1, 2, 7: Hutton, 1879, p. 329: Gruvel, 1905, p. 273: Pilsbry, 1916, p. 273, pl. 65, figs. 3, 4.

Specific Diagnosis.—“Shell crown-shaped, with longitudinal convex ribs, having their edges crenated; orifice hexagonal: radii moderately thick, very broad: terga absent or rudimentary.” (Darwin.)

Localities.—Waikouaiti, on a whale (F. W. Hutton); on whale (specimens in Auckland Museum).

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Chamaesipho columna (Spengler).

Lepas columna Spengler, 1790, Skrifter Naturhist. Selbskabet, B. 1, Tab. vi, fig. 6. Chamaesipho columna Darwin, 1854, p. 470, pl. 19, figs. 3a-3c; Hutton, 1879, p. 329; Gruvel, 1905, p. 282, figs. 306, 307.

Specific Diagnosis.—“Sutures, excepting during early youth, generally obliterated both externally and internally: tergum with small pits for attachment of depressor muscle.” (Darwin.)

Localities.—Cuvier Island (Grenfell and Barr); Nelson (L. S. Jennings); Shag Point, Otago (W. R. B. Oliver).

List of References.

Annandale, N., 1911. Description of an Undescribed Barnacle of the Genus Scalpellum from New Zealand, Trans. N.Z. Inst., vol. 43, pp. 164–65, with text-figs. 1–4.

Borradaile, L. A., 1916. Crustacea, Part III, Cirripedia, in British Antarctic (“Terra Nova”) Expedition, 1910.

—— 1917. Barnacles from the Hull of the “Terra Nova,” a Note, Ann. Mag. Nat. Hist., ser. 8, vol. 19, pp. 229–30.

Chilton, C., 1909. The Crustacea of the Subantarctic Islands of New Zealand, The Subantarctic Islands of New Zealand, pp. 601–71 (with 19 figures in text), Wellington, N.Z.

—— 1911A. The Crustacea of the Kermadec Islands, Trans. N.Z. Inst., vol. 43, pp. 546–73 (with text-figures).

—— 1911B. Scientific Results of the New Zealand Government Trawling Expedition, 1907, Crustacea, Rec. Canterbury Museum, vol. 1, pp. 285–312, pl. 58 and text-figures.

—— 1911C. Note on the Dispersal of Marine Crustacea by means of Ships, Trans. N.Z. Inst., vol. 43, pp. 131–33.

Darwin, C., 1851. Monograph of the Cirripedia: the Lepadidae, Ray Society.

—— 1854. Monograph of the Cirripedia: the Balanidae and the Verrucidae, Ray Society.

Filhol, H., 1885. Mission de l'île Campbell, in Recu. Passage Véus, vol. 3, ii, Zool., pp. 349–510, pls. 38–55.

Gruvel, A., 1905. Monographie des Cirrhipèdes, Paris.

Hutton, F. W., 1879. List of the New Zealand Cirripedia in the Otago Museum, Trans. N.Z. Inst., vol. 11, pp. 328–30.

Jennings, L. S., 1915. Pedunculate Cirripedia of New Zealand and Neighbouring Islands, Trans. N.Z. Inst., vol. 47, pp. 285–93, with text-figures.

Pilsbry, H. A., 1907. Barnacles (Cirripedia) contained in the Collections of the U.S. National Museum, U.S. National Museum Bulletin 60.

—— 1909. Barnacles of Japan and Bering Sea, Bull. Bureau Fisheries, U.S.A., vol. 29.

—— 1911. On the Nomenclature of Cirripedia, Zool. Anz., Bd. 37, pp. 33–35.

—— 1916. Sessile Barnacles (Cirripedia) contained in the Collections of the U.S. National Museum, including a Monograph of the American Species, U.S. National Museum Bulletin 93.

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Art. IV.—A New Species of Hypolepis.

[Read before the Auckland Institute, 11th December, 1917, received by Editors, 24th December, 1917; issued separately, 24th May, 1918.]

Hypolepsis Petrieana sp. nov. Carse.

Hypolepis bipinnata, H. millefolio Hook. affinis: differt stipite glabro ± tuberculato; ramis primariis numerosis parum distantibus. Superioribus a rhachi angulis valde obtusis provenientibus; pinnis secundariis in lobos breves late obcuneatos, acutos, subacutos, v. fere obtusos, integros v. ± alte (plerumque a margine superiore) incisos, pro parte maxima alternos, sectis.

Sori parvi rotundati pauci, in lobis singulis, 1, rarius 2.

Rhizoma tenue, repens, squamis linearibus ferrugineis dense vestitum.

This undoubtedly new species of Hypolepis was discovered in December, 1907, by Mr. D. Petrie, M.A., Ph.D., with whose name I have pleasure in associating it.

Rhizome slender, creeping, thickly covered with linear rusty scales.

Stipes 4–6 in. long, rigid, moderately stout, erect, yellow (as are the rhachis and primary costae) or the lower part brownish, glabrous, somewhat rough with scattered depressed tubercles.

Fronds 12–14 in. long, 8–10 in. broad, broadly obcuneate-ovate, subrigid, bipinnate, secondary pinnae pinnatifid or their lower part pinnatisect; primary branches numerous, rather closely placed, the upper diverging almost at right angles.

Rhachis and primary costae sparingly or somewhat closely clothed with delicate crisped hairs; lower primary pinnae narrow ovate – lanceolate, 6–8 in. long, suberect or ascending, shortly stipitate, the upper gradually shorter, narrower, and more strongly diverging; secondary pinnae very shortly stipitate, broadly linear, 2 ¼ in. long or less, cut half-way down, or almost to the costa, into short entire or ± deeply cut (mostly at the upper edge) broadly obcuneate, acute, subacute, or almost obtuse, usually alternate, lobes, that are glabrous above and nearly so below; midrib with a few short hairs, chiefly on the under-surface.

Sori 1, or rarely 2, on each ultimate lobe, small, rounded, the common one partially covered by a very short reflexed lobule projecting from the upper basal border of the lobe, the second (when present) placed about halfway up the lower side of the lobe and more or less covered by its slightly expanded and recurved margin.

Indusium composed of the almost unaltered reflexed portions of the lobes described above.

Hab.—Vicinity of Otorohanga, Waipa County, and Port Charles, Coromandel County. D. Petrie!

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Art. V.—The Stratigraphical Relationship of the Weka Pass Stone and
the Amuri Limestone
.*

[Read before the Philosophical Institute of Canterbury, 5th September, 1917; received by Editors, 31st December, 1917; issued separately, 24th May, 1918.]

Plates IVVII.
Contents.

  • Introduction.

  • Detailed Description of the Limestones.

  • Amuri Limestone.

  • The Nodular Layer.

  • Phosphatic Nodules.

  • Microscopic Description of a Typical Nodule.

  • Nodular Limestone.

  • Weka Pass Stone.

  • Historical Summary.

  • Detailed Descriptions of Important Sections.

  • Weka Pass.

  • Main Branch of Weka Creek.

  • Upper Waipara.

  • North-east Slope of Mount Grey.

  • South Branch of Omihi Creek.

  • North Side of Waikari Creek between Waikari and Scargill.

  • Gore Bay.

  • South Bank of the Hurunui.

  • On Coast South of the Blyth River.

  • Stonyhurst, in a Creek near the Homestead.

  • Motunau River.

  • Boundary Creek.

  • South Side of Amuri Bluff.

  • On Bluff North of the Mikonui Creek.

  • Near Maori Village on South Side of Kaikoura Peninsula.

  • North of Atiu Point, East End of Kaikoura Peninsula.

  • North Side of Kaikoura Peninsula.

  • Mouth of Lyell Creek, Kaikoura.

  • Puhipuhi Valley and Long Creek.

  • Contact of the Grey Marl with the Underlying Limestone.

  • Main Branch of Weka Creek.

  • Near Old Wharf, North Side of Kaikoura Peninsula.

  • East Side of Kaikoura Peninsula.

  • South Side of Amuri Bluff.

  • Evidence, that the Series is Conformable.

  • The Peculiarities of the Junction of the Amuri Limestone and Weka Pass Stone.

Introduction.

The area referred to in this paper stretches from the neighbourhood of the Waipara River in a north-easterly direction across the Hurunui River, up the coast past Amuri Bluff, to just north of Kaikoura, a total distance of

[Footnote] * We desire to state that we have been enabled to make the observations recorded in this paper largely through the award of a grant by the New Zealand Institute for research work on the phosphate-bearing rocks of Canterbury.

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about eighty miles (see map). Throughout the region there is a great development of the Tertiary sedimentaries, and some of the localities have been looked on as classical in the discussion of various points relating to New Zealand stratigraphy. Notably is this true of the areas in proximity to the Waipara River, the Weka Pass, and Amuri Bluff, probably no parts of New Zealand furnishing better opportunities for studying the relationship of beds with a Cretaceous fauna to those with a Tertiary fauna. Nevertheless there have been and now exist remarkable discrepancies of opinion on the part of writers, and as we have had in the course of our search for phosphatic rock ample opportunities to study the relationship of the beds in different localities, and, as many miles of outcrops have been carefully examined, especially those concerning which the discussion has been keenest, we consider it appropriate to place on record the result of those observations, as far as they affect the question of the stratigraphy, in the hope that they may aid in a definite opinion as to the points at issue being arrived at.

The most important question suggested by the investigation is the matter of the conformity or unconformity of two limestones which are

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Locality-map of part of the east coast of the South Island of New Zealand.

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typically developed in the southern part of the area. The beds involved in this discussion are as follows, commencing from the bottom of the series:—

(1.)

Greensand.

(2.)

The Amuri limestone, an argillaceous limestone, named from its great development in the neighbourhood of Amuri Bluff, but also occurring, outside the area under consideration, in the valleys of the Clarence and Awatere, and perhaps in the south of the North Island.

(3.)

A nodular band, less than 1 ft. thick, composed of phosphatic material of two kinds in a matrix of greensand or marl.

(4.)

The Weka Pass stone, a glauconitic arenaceous limestone as it occurs in the typical locality at Weka Pass, but probably equivalent to the higher parts of the Amuri limestone elsewhere, and perhaps to the lower part of the next succeeding higher bed in localities near Kaikoura and Amuri Bluff.

(5.)

The Grey marl, in its lower portions a glauconitic, arenaceous marl, which in its higher parts in some localities becomes distinctly argillaceous and takes on a true marly facies, and at times becomes decidedly sandy as it passes up into the next higher member of the series.

There follows a more detailed description of the second, third, and fourth of these beds, which are the most important as far as this discussion is concerned.

Detailed Description of the Limestones.

Amuri Limestone.

Although the macroscopic properties of the Amuri limestone have been fully described previously by various observers and its microscopic characters have been dealt with by Marshall (1916, p. 95), it may be as well to restate its salient features in this connection.

As typically developed south of Kaikoura it is an argillaceous limestone, breaking up freely into quadrangular blocks owing to the presence of a well-defined system of cross-joints, a property which is eminently characteristic of it wherever it occurs. Owing to some of these blocks being thin and flaky, its surface takes on a tile-like appearance, especially where inclined beds are exposed on a shore-platform. This character is shown throughout the whole thickness of the limestone at Kaikoura and at Amuri Bluff, but farther south, as at Weka Pass, the so-called Weka Pass stone (the higher part of the Amuri limestone as maintained by the authors) does not exhibit to a marked degree this jointed structure, though echoes of it are undoubtedly present.

The rock is at times chalky in texture, but is usually hard and occasionally crystalline, especially where it has been subjected to pressures resulting from earth-movements. Notably is this the case at Kaikoura, where it sometimes takes on a subschistose character. Mention should be made here of the chalk deposit at Oxford, which represents this rock in the Waimakariri basin, judging from stratigraphical and lithological evidence.

The microscope shows the presence of numerous grains of glauconite even in the white-coloured rock, but distinct layers and lenticules of green-sand occur at times, as can be seen in localities like Weka Pass, though it occurs more freely farther north. At Kaikoura it occurs right through the stone, but more especially at the higher levels, where it is organized into

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well-defined layers, this being especially the case above the zone of phosphatic nodules. Similar well-defined interstratified greensand bands are noted by McKay and by Thomson as occurring in the development of Amuri limestone in the valley of the Clarence. This is important, seeing that this higher portion, notably at Kaikoura, has been definitely recognized by various authorities as belonging to the Amuri limestone and not separated from it by any unconformity.

Another notable constituent of the limestone is flint, which occurs in lenticules and in irregular masses, as has been fully described by Thomson (1916, pp. 52–58). In Marlborough flint is specially important, but the amount progressively diminishes on being traced south. It is a well-marked constituent at Amuri Bluff and at Gore Bay, and it also occurs in the chalk deposits at Oxford, thus having a somewhat wider distribution than might be inferred from Thomson's paper. The flint is found both above and below the layer of nodules in the Kaikoura and Amuri Bluff districts, so that its presence or absence cannot be regarded as a criterion of age. Thomson has regarded the flint as formed by chemical precipitation (1916, p. 56). If that is so it must have been precipitated subsequently to the boring of the limestone, unless the boring animals have been able to penetrate flint itself, as the flint occurring in situ occasionally shows burrows filled with glauconitic material.

The lower portions of this limestone are decidedly more argillaceous, and merge into a true marl.

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Table I.—Analyses of Amuri Limestone from Weka Pass.
(1.) (2.) (3.) (4.) (5.)
SiO2 11.12 7.52 6.74 7.25 14.45 Al2O3 1.78 1.64 1.50 0.66 1.03
Fe2O3 0.54 0.77
CaO 46.55 49.33 49.75 49.64 45.67
MgO 0.22 0.22 0.67 0.45 0.61
P2O5 0.28 0.19 0.12 n.d. n.d.
CO2 36.41 38.49 38.76 39.0 35.89
Moisture and organic matter 1.74 1.05 1.20 2.06 1.58
Alkalis, & c. 1.90 1.56 1.26 0.40
100.00 100.00 100.00 100.00 100.00
(1.)

Amuri limestone at contact, near railway viaduct.

(2.)

Amuri limestone, upper layer, same locality.

(3.)

Amuri limestone, 35 ft. below upper surface.

(4.)

Average sample, thickness of 40 ft.

(5.)

Sample 2 ft. below upper surface.

Table II.—Partial Analyses of Amuri Limestone from Kaikoura.
(1.) (2.)
Insoluble in acid 11.96 10.40
Fe2O3 and Al2O3 3.20 4.80
CaCO3 82.60 82.62
P2O5 0.57 0.51
(1.)

Sample 2 ft. to 4ft. below contact.

(2.)

Sample at the contact.

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The Nodular Layer.

This layer is most important, as giving some idea of the conditions which obtained in the interval between the deposit of the two limestones, and therefore it will be described in detail. The most important constituent in point of volume is a calcareous greensand which fills borings in the upper surface of the Amuri limestone and passes up into the overlying Weka Pass stone, the lower parts of which are decidedly glauconitic, and there is apparently no pronounced line of division between them. Included in this matrix of greensand are numerous nodules which are more or less phosphatic, so that it may be called the phosphatic nodule bed. This nodular material is of two kinds—(1) true phosphatic nodules, and (2) nodular masses of Amuri limestone.

Phosphatic Nodules.—The descriptions of similar nodules occurring in deep water south of the Cape of Good Hope, on the Agulhas Bank, as given in the reports of the “Challenger” Expedition (“Deep-sea Deposits,” p. 396) applies so exactly that we can use the same words to describe appropriately those occurring in our own limestones. The description is as follows: “The concretions vary from 1 to 3 cm. in greatest diameter; exceptionally they may attain from 4 to 6 cm. in diameter. They are surmounted by protuberances, penetrated by more or less profound perforations, and have on the whole a capricious form, being sometimes mamillated with rounded contours and at others angular. Their surface has generally a glazed appearance and is usually covered with a thin dirty brown coating, a discoloration due to the oxides of iron and manganese.” The description further points out that grains of glauconite form a notable constituent in their composition, and especially is this the case in those from shallower water, which are larger and have a greenish-coloured external appearance. This is important, as the great majority of those found in the limestones have a greenish-coloured external appearance. The concretions are described as being hard and tenacious, “the fundamental mass, in spite of its earthy aspect, being compact, and having a hardness that does not exceed 5.” This description so fits the nodules in the greensand layer that one cannot help suspecting a similarity of origin in the two cases.

For the purpose of comparison of the chemical composition we quote three analyses—the first, of one of the Agulhas Bank nodules; the second, one cited by McKay (1887, p. 84), of a nodule from the greensand layer at the Weka Pass; the third, of a nodule collected by us at Boundary Creek.

Table III.
(1.) (2.) (3.)
SiO2 14.78 17.25
Al2O3 3.34
Fe2O3 3.87
CaO 39.58 42.17 45.90
MgO 0.84 0.72
P2O5 19.96 17.45 21.12
CO2 12.05 15.36
SO2 1.37

It is unfortunate that the second and third analyses are not more complete, but the general similarity of the results obtained will be noted.

The nodules from deeper water, as pointed out subsequently in the report (p. 393), differ from those just referred to, and the same applies

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to those reported on by Murray as occurring in the “Bottom deposits” obtained by the “Blake.”*

The association of nodules with greensand does not, however, point to a genetic connection between the two, since nodules are found on the bottom of the present sea not associated therewith. They are of different origin and character, as may be inferred from the report on the “Blake” deposits, and as is noted in the report of the “Challenger.” The point is well brought out by Collet and Lee:—

“La glauconie et ses concrétions phosphatées se forment actuellement sur le fond des mers, existe-t-il une relation entre ces deux formations au point de vue de leur genèse? Cette question se pose naturellement quand on étudie les dépôts marins, et nous croyons être maintenant en mesure d'y répondre négativement.

“Les concrétions phosphatées sont pour ainsi dire l'image du fond dans lequel on les rencontre, ce qui prouve bien leur formation in situ. Ce fond est-il sable vert, comme dans le cas de l'Agulhas Bank, les concrétions phosphatées contiendront de la glauconie en grand abondance; est-il une boue è globigérines formée non loin du continent mais en eau profonde (3,475 mètres pour un des échantillons du Challenger), la concrétion sera entièrement formée de globigérines avec minéraux détritiques mais sans glauconie.”

Therefore the association of the greensand with phosphate nodules in the case of the limestones merely indicates that the nodules were formed on a sea-bottom at such a depth that greensands were being laid down at the same time. The depth was approximately that at which the limestones also were being deposited, as is evidenced by the interstratification of the greensand and limestone and the presence of glauconite grains in the limestone. The Amuri limestone has been shown by Marshall (1916, p. 95) to be practically equivalent to an ooze, and its chemical composition shows that it contains over 80 per cent. of CaCO3, so that it may be concluded, judging from the table given in the “Challenger” report (p. 79), that the depth was under 1,000 fathoms.

Microscopic Description of a Typical Nodule.—Under the microscope the base consists of irresolvable matter, probably calcite, with numerous tests of Foraminifera, and small fragments of quartz, feldspar, and occasionally mica. The base contains patches of microspherulitic structure, exhibiting between crossed nicols a well-marked cross with dark arms parallel to the cross-wires. They resemble to some extent small spherules of chalcedony, but from their high polarization colours they are no doubt composed of radiating fibres of calcite. There is a greenish stain of glauconite all through the slide, and the mineral at times forms distinct grains, in many cases filling the cavities of Foraminifera. These last are very numerous and constitute the bulk of the rock. The following genera were recognized: Globigerina (which is by far the most important), Textularia, Nodosaria, Rotalia. Radiolaria are also present. The glauconite is light-green as a rule, but occasionally dark-green and black aggregates also occur as a result of the peroxidation of the iron present. Small fragments of bone were also noted in one of the nodules.

Nodular Limestone.—This second class of phosphatic material consists of detached portions of the Amuri limestone included in the greensand,

[Footnote] * Bull. Mus. Comp. Zool., vol. 12, p. 52, 1885–86.

[Footnote] † Recherches sur la glauconie, Proc. Roy. Soc. Edin., vol. 26, pt. 4, p. 266, 1906.

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which have an origin quite distinct from the true phosphatic nodules referred to previously. The nodular limestone, though easily recognized in the hand-specimen, differs little from the true nodules under the microscope, except that it is less glauconitic and approaches very closely to normal Amuri limestone. There can be no doubt that for a considerable period the limestone formed the ocean-floor (as is indicated by the phosphatic nodules), and that it was honeycombed by the borings and burrows of marine organisms operating at that depth, and that the additional phosphatic material was obtained from the ordinary limestone by a process of concentration, and from remains of those organisms responsible for the burrows. It is quite intelligible that during a period of halt in the deposition the solvent action of sea-water would cause a disappearance of a portion of the floor, and, as the phosphatic material is less soluble than the calcareous, some concentration of the phosphate would result.

This idea finds strong support in the following partial analyses of specimens obtained at Weka Pass. At this particular section the Amuri limestone is seen to be perforated to a depth of 4 ft. 6 in., the cavities being filled with the calcareous greensand that represents the overlying Weka Pass stone at this locality. The upper 18 in. of the Amuri limestone is much honeycombed with burrows, and completely detached fragments are to be found lying within the Weka Pass stone as much as 6 in. above the present surface of the Amuri limestone. It is to be understood that we look upon these nodular fragments as remnants of the original upper portion of the Amuri limestone which, during a halt in the deposition, was broken down by the combined action of boring-animals and solution by sea-water, some at least of the phosphate so set free being concentrated in the residual portions of limestone.

Table IV.
(1.) (2.) (3.) (4.)
Insoluble in acid 12.08 11.95 11.52 55.68
CaO 48.65 42.20 44.85
P2O5 0.16 0.45 4.09 1.34
(1.)

Sample 2 ft. from present surface of Amuri limestone.

(2.)

Sample from upper 6 in. of honeycombed portion of Amuri limestone.

(3.)

Detached nodules of Amuri limestone lying in the Weka Pass stone a few inches above the present surface of the Amuri limestone.

(4.)

Lower 2 ft. of Weka Pass stone.

In both types of nodules there is little difference from the associated limestone in the character of the Foraminifera and general structure of the rock, and they seem to have been formed under similar conditions. The description applies to specimens from Amuri Bluff and Stonyhurst equally with those from Weka Pass.

Under the microscope the material that fills the borings appears to be composed of much the same material as the associated limestone, and resembles in texture the Amuri limestone rather than the Weka Pass stone. There is, however, more granular glauconite, and there are more numerous shreds of mica and fragments of quartz. The glauconite does not fill the cavities in the Foraminifera so markedly, though undoubtedly some are filled. The genera of Foraminifera appear to be the same as in the Amuri limestone, Globigerina, Nodosaria, and Rotalia being clearly recognizable.

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Weka Pass Stone.

In the typical locality near Weka Pass this rock consists of an arenaceous, glauconitic limestone. In its lower portion the rock presents the facies of a calcareous greensand of very fine grain, with a comparatively low percentage of calcium carbonate, but this percentage increases in the higher levels. (See analyses.) Specks of glauconite are, however, distributed throughout the rock. It breaks at times into quadrangular blocks, but rarely with the tily arrangement which characterizes Amuri limestone, though at times there is considerable similarity between the two rocks. Under the microscope it appears to be composed largely of Foraminifera, notably Globigerina, with a considerable amount of quartz and occasional shreds of biotite. The glauconite exists as grains, sometimes as a stain on the quartz, and occasionally filling the cavities of Foraminifera. As compared with Amuri limestone it is coarser in texture, more glauconitic and arenaceous; but the Foraminifera appear to be the same, and, as in the former case, have their cavities filled with calcareous material. The depth at which deposition took place would in all probability be slightly shallower than that at which the Amuri limestone was laid down.

Away from the typical locality the rock exhibits considerable variation. It is sometimes more glauconitic, and in fact passes into a calcareous greensand; while in other places it becomes more sandy and friable. The former of these two facies represents in all probability a deposit either in shallower water or nearer a shore-line, but there is no doubt as to its equivalence to the more calcareous rock. It is perhaps not truly synchronous, in that it may mean the gradual extension of the deposit into shallower water as physical conditions in the area changed; but the stratigraphical position and the relationship of the two facies to the underlying Amuri limestone are practically identical.

Table V.—Analyses of Weka Pass Stone.
(1.) (2.)
SiO2 34.95 22.51
Al2O3 6.44 3.92
Fe2O3 2.76 2.08
CoCO3 47.62 67.60
MgCO3 1.46 0.80
CaO 1.50 0.80
P2O5 n.d. n.d.
Organic matter and water 3.50 2.29
(1.)

Weka Pass stone 2 ft. above Amuri limestone. (Coll. J. Park.)

(2.)

Weka Pass stone, average sample “from Waikari end of Weka Pass, from cliffs N.E. of stream a few chains above the railway viaduct.” (Coll. J. Park.)

Historical Summary.

The following is a summary of the opinions held by the authors cited in the bibliography at the end of the paper, in the order of time in which they are expressed:—

Hector says (1869, p. xii), “The above (3 and 4) [grey marl] rest unconformably on blue and grey marly sandstone, sometimes passing into chalk, the formation resembling, in mineral character, the English chalk marl. In the same formation, farther north, flints occur.” There is some doubt

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concerning the proper interpretation of the beds as detailed by Hector, but the record of cup-shaped Bryozoa as occurring in (4) evidently points to what is called the grey marl in the Waipara section, and the beds with flints to the Amuri limestone, and the grey marly sandstone to the Weka Pass stone. It is evident, therefore, that Hector did not recognize an unconformity within the beds indicated above.

Haast evidently considered the two beds of limestone as quite conformable. He says (1879, p. 297), “In some localities a break seems to occur between the upper and lower calcareous series, as, for instance, in the Weka Pass ranges, where the lower, more calcareous strata are sometimes separated from the glauconitic massive upper beds by a small band of greensand containing concretions of a more calcareous nature. However, in many other localities this small bed does not occur, and the boundary between the two series is either gradual or sharpy defined. Moreover, the upper beds are found to be always conformable upon the lower where the latter exists, being, in fact, a continuation of the same series, and, owing to the sinking of the land, of greater horizontal extent than the more calcareous beds underlying them.” We have quoted this description in full as it appears to us to explain concisely the whole case.

Hutton (1877, 1885, 1888) always maintained the unconformable relationship between the Amuri limestone and the Weka Pass stone, urging that the contact was a normal erosion-surface, and in none of his writings cited in the bibliography does he depart in the slightest from this position.

McKay (1881, 1886, 1887) considered the sequence conformable.

Thus it is that, among the older geologists of this country who have reported on this matter, three agree that the sequence is conformable, while one maintains the contrary.

We come now to the opinions of those of a more modern date. The first to be considered is that of Professor Park, who forms a kind of link with the older geologists. His views are by no means certain, and exhibit considerable evolutionary development. In his report published in 1888 he says, “As a result of the examination of many of the magnificent sections between the Weka Pass and the Waipara, I am strongly of the opinion that a complete sequence of beds exists from the base of the Cretaceo-Tertiary to the close of the Pareora formation, although the varying character of the deposits and their fossil remains show that the sea-bottom on which they were deposited was subject to frequent oscillation.” Again (1905, p. 546), he says, “Captain Hutton contends that there is an unconformity between the Weka Pass stone and the Amuri limestone. I have carefully examined the line of contact of the two rocks, but was unable to find any evidence of unconformity; and on this point my view coincides with that of Sir James Hector, Sir Julius von Haast, and Mr. McKay.” In his Geology of New Zealand (1910) Park evidently regards the two limestones as conformable, a position which he maintained in 1911 (p. 546). Next year, however, as a result of the finding of Pecten huttoni in the Weka Pass stone, he moved his unconformity to the base of the Weka Pass stone, which he then stated lay conformably under the Mount Brown limestone, although he had in 1888 demonstrated on stratigraphical grounds the existence of an unconformity between them. His position, therefore, seems somewhat obscure.

Marshall (1911, 1912) has always maintained the physical conformity between the beds of this series, and in this he has been supported by Cotton and Speight, both in conjunction with him (1911) and independently (1912).

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Thomson also (1912, p. 8) has noted the physical conformity of the beds in the typical locality, whereas Morgan (1915, pp. 90–93), the latest writer on the subject, as a result of a hurried visit came to the conclusion that the top of the Amuri limestone presented a true erosion surface, but as the result of more complete examination of the relationship of the beds expresses himself in a less dogmatic manner (1916, pp. 17–28, and 1916A, pp. 10–11), and has evidently some doubts as to the correctness of his first interpretation, although he still agrees tentatively with Hutton and Park in his latest pronouncement.

Detailed Descriptions of Important Sections.

In order to arrive at a thorough appreciation of the problem a detailed description will be given of all localities where contacts occur from the neighbourhood of Mount Grey to just north of Kaikoura, and from the sea-coast as far inland as limestones occur which furnish any evidence. This ranges over a belt of country nearly one hundred miles in length and with a maximum breadth of fifteen miles. The localities first taken are those in the neighbourhood of Weka Pass, the typical locality; then those near the Waipara River and Mount Grey. They are followed north-east to Cheviot, when a return is made along the coast by way of the Hurunui mouth, Stonyhurst, and Motunau; and the series concludes with those at Amuri Bluff, Kaikoura, and the Puhipuhi River. We do not think that any important locality in that area has been omitted from consideration. It will be noticed that there is a general similarity of the sections throughout the area, both in its length and its breadth, which the advocates of unconformity will find difficult to explain, while the evidence for conformity is particularly strong.

Weka Pass.

Good contacts can be seen at various places in the neighbourhood of the pass—e.g., on the roadside just past Seal Rock, in the little gorge near the viaduct, on the northern face of the escarpment just east of the viaduct, and on both sides of the denuded anticline to the west of the viaduct. (Plates IV and V.) The following description fits in each case:—

(1.)

Amuri limestone: White, and jointed into flaky quadrangular blocks, the upper 2 ft. or more being bored by marine worms and the casts filled with glauconitic limestone. The amount of boring increases progressively upward till what may be called the transitional layer is reached.

(2.)

Transitional layer: This consists in its lower part of Amuri limestone material thoroughly bored, with the interstices filled with glauconitic limestone. The result of boring increases progressively, and the quantity of glauconitic material also increases pari passu. The upper 6 in. is completely bored, so that peninsulas of Amuri limestone project at times into the overlying glauconitic layer, and at times become detached and resemble subangular pebbles in appearance. They are more phosphatic than the underlying limestones, and the included glauconitic limestone is more phosphatic than the overlying glauconitic layer. The number of residual fragments of limestone decreases till they are entirely absent from the distinct layer of strongly glauconitic limestone. Included in this band are small angular nodules, green or black in colour, which are strongly phosphatic. Very occasionally, small well-rounded pebbles of quartz, about ¼ in. in diameter, are met with.

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Plate IV.
Contact of Amuri limestone and Weka Pass stone, showing nodules of phosphatized Amuri limestone, on roadside, Weka Pass

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Plate V.
Contact of Amuri limestone with Weka Pass stone on escarpment east of viaduct, Weka Pass Detached fragments of Amuri limestone can be seen in the Weka Pass stone

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(3.)

Glauconitic calcareous sandstone: This is a distinct layer, about 6 in. thick, of strongly glauconitic fine-grained calcareous sandstone, which passes up into Weka Pass stone.

(4.)

Weka Pass stone: This is a distinctly glauconitic, arenaceous limestone. The green and black nodules which mark the contact appear to diminish in number on going south-west along the escarpment, but they are occasionally present and so mark a continuous horizon; but on approaching the Waipara River the difference between typical Amuri limestone and Weka Pass stone disappears, and the contact becomes indefinite—in fact, the two beds merge into one limestone without any break.

Main Branch of Weka Creek.

There is an excellent exposure of the contact in the branch of the Weka Creek north-west of the main road, just where it is crossed by the subsidiary road running from Weka Pass behind the Mount Brown escarpment in the direction of the Waipara River. The stream has in this locality cut a deep narrow gorge right across the strike, and the contacts of the Weka Pass stone with the underlying Amuri limestone as well as with the overlying grey marl are excellently shown, both being quite conformable.

In the case of the former contact we have the following sequence:—

(1.)

Amuri limestone, breaking into quadrangular blocks, with interstitial calcareous greensand in layers parallel to the bedding in its upper portions, very occasional burrows extending to 6 ft. below the actual junction. On approaching the junction the amount of greensand becomes greater, both in layers and in burrows, till near the contact the two form nearly equal proportions in the rock. Thereafter the Amuri limestone diminishes in importance, and inclusions of limestone in the greensand become rare. Dark-green and black nodules (phosphatic) as well as ironstone concretions also occur. The thickness of the layer where the two occur is about 12 in.

(2.)

Greensand layer, without inclusions of Amuri limestone, about 1 ft. in thickness, but passing up into

(3.)

Weka Pass stone in its typical development.

The contact between the two limestones is clearly seen on the escarpment to the north, and is visible at times on the south as far as a limestone knob a mile south of the creek, when for some distance towards the Waipara the junction is obscured. As far as it is visible it displays the same characteristic features.

Upper Waipara.

Excellent sections showing the relationship of the two facies of the limestone are to be seen above the limestone gorge of the Waipara River along the bold escarpment facing north-west. At the gorge itself there is the following sequence:—

(1.)

The marly facies of the Amuri limestone forms the lowest portion in this locality, and passes up into

(2.)

Typical jointed Amuri limestone with interstratified bands of argillaceous and glauconitic limestone. The upper layer of Amuri limestone is a compact white rock containing glauconite, the upper 6 ft. or 8 ft. with a concretionary fracture and passing up into

(3.)

Weka Pass stone of more than usual glauconitic character.

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No nodules r borings are present on the line of junction, which is indistinct one rock gradually passing into the other.

Along the escarpment to the south-west the same general features are to be observed, the Amuri limestone being decidedly glauconitic at times and the greensand layer at the junction more marked than near the gorge, while the Weka Pass stone exhibits in places the typical facies, though in others it is like the Amuri limestone, and in others again it is of sandy texture, approaching a freestone, and is so friable that it can be rubbed into powder with the fingers.

At the point where shells of Pecten huttoni are found in the Weka Pass stone, which is a few chains east of the low part of the escarpment where the road crosses, the junction presents the usual features of worm-borings and the presence of scattered dark phosphatic nodules, while on the weathered surface of the Amuri limestone there are small protuberances of limestone, evidently more resistant than the remainder of the rock, and owing their preservation to the presence in them of an amount of calcium phosphate in excess of that in the surrounding rock.

When traced west the limestone outcrop passes over into the watershed of Boby's Creek, and in the bed of its most northerly tributary an excellent exposure is to be seen. This is as follows:—

(1.)

Amuri limestone, the upper 3 ft. bored more and more till the junction is reached, the borings being filled with greensand. Detached fragments of more phosphatized limestone occur along the junction. The limestone is here much thinner than it is on the escarpment to the north-east, and thins out still more when followed to the south-west towards Mount Grey.

(2.)

Nodular layer: This consists mostly of detached fragments of limestone, the true nodules being small; all are enclosed in a greensand matrix. A well-rounded pebble of greywacke was found embedded near the junction, indicating in all probability the close proximity of a shore-line. This passes up into

(3.)

Greensand, with fewer and fewer nodules.

(4.)

Weka Pass stone, more glauconitic than usual, as is usually found as the deposits approach an outstanding greywacke mass; in this case it is that of Mount Grey. In the lower part of this layer shells of Pecten huttoni were found in a somewhat poor state of preservation.

The strike of all the beds is north-east and south-west, with a dip to the south-east of 35°.

No evidence of unconformity, excepting the pebble, is given by this locality, although it affords ample opportunity for locating one did it exist. The interstratification of glauconitic limestone in the Amuri stone indicates that no great change in depth occurred between the deposit of the typical Amuri limestone and the Weka Pass stone, the interstratification of the glauconitic material in the former preparing the way for the final development of the pronounced glauconitic type.

North-east Slope of Mount Grey.

The fine escarpment which runs south-west through Mount Brown towards Mount Grey is deflected when it reaches the vicinity of the mass of greywacke of which the latter is composed, no doubt partially owing to earth-movements, of which there is decided evidence in the locality.

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A well-defined fault-scarp runs along the eastern face of the mountain in a north-west and south-east direction in a line with the western margin of the depression which continues towards Heathstock and the Upper Waipara basin. On the western side of this, in the vicinity of Mount Mason and elsewhere, there is evidence of deformation where the limestones abut against the older rocks. This line of deformation evidently belongs to the series of north-west and south-east earth-fractures which are characteristic of the mountain region of Canterbury. As a result of this and related movements the Mount Brown beds and the underlying limestones are bent round till on the divide between Boby's Creek and Kowai River they strike north-west and dip to the north-east at high angles, about 70°. The edges of the beds are thus exposed, and the relations of the Amuri limestone to the beds immediately overlying it are well seen in one or two places. The sequence is here as follows:—

(1.)

Amuri limestone, of the usual type, well jointed, and not more than 25 ft. thick; it thus shows the characteristic thinning-out as it approaches a shore-line. In its upper layers it is glauconitic, and deeply bored, with the borings filled with greensand.

(2.)

Nodular layer: This is about 4 ft. wide, with pieces of limestone in a matrix of greensand. This bed is closed with a fairly well-defined layer of fragments in which limestone predominates over greensand, as if there were a partial reversion to limestone conditions when this part of the bed was being deposited. The calcareous nodules are distinctly bored, and show a marked qualitative reaction for phosphoric acid. There are occasional small, rounded, dark-greenish nodules, up to ¾ in. in diameter, but these are more important in the next bed.

(3.)

Calcareous greensand, strongly glauconitic. It appears that the Weka Pass stone takes on this decidedly glauconitic facies as it approaches a shore-line, and also the phosphatic nodules are apparently more numerous under these conditions, suggesting a resemblance to the conditions obtaining on sea-bottoms of the present day where greensands and green muds are associated with these nodules.

South Branch of Omihi Creek.

South-east of the Omihi Valley, and dividing its drainage area from that of the slopes facing seaward, lies the prominent limestone escarpment of the Cass, or Limestone, Range as it is sometimes called. On its northern side there are excellent exposures of the limestones and the underlying sands and sandstones resting unconformably on the Trias-Jura beds. Owing to a fault which runs approximately north-east and south-west, with a throw of some 1,000 ft. to the north-west, the outcrops are repeated, and we thus get two sections which show the horizon of the nodular layer. They exhibit a striking difference, however. One section has a facies which shows the proximity of a shore-line, in agreement with the fact that the Trias-Jura beds are in evidence but a few hundred yards away in the direction of the rise of the beds, whereas the other section, about a mile and a quarter to the south-east, has a facies which is characteristic of deeper water.

The first of these sections is well displayed near a small waterfall on the east side of the road which runs south past the shepherd's hut in the direction of the limestone escarpment. The typical Amuri limestone is here

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absent, but it is represented stratigraphically by a strongly glauconitic limestone, whose glauconitic character is strongly marked in the flaky quadrangular blocks into which the stone is divided, but more strongly still in the interstitial portions. A well-defined layer of nodules occurs in this limestone, the matrix being a markedly glauconitic limestone. The nodules are of two types—(1) ordinary phosphatized limestone, and (2) small dark-green nodules up to 1 in. in diameter, scattered through the nodular layer and through the next 4 ft. of the bed above. The nodular layer is not so well defined as usual, but passes gradually into the beds above and below it. Worm-borings are a feature of the occurrence, and there is an entire absence of any evidence of unconformity. The whole arrangement gives a good illustration of the modification in the character of the Amuri limestone as it approaches a shore-line, and supports the contention of some writers that greensand can be laid down in comparatively shallow water.

The other type of contact showing the relations of the Amuri limestone to the Weka Pass stone can be clearly seen on the northern slope of the escarpment to the south at an elevation of between 1,600 ft. and 1,700 ft. The following is a description of the contact as seen over a considerable length of the escarpment: The Amuri limestone is from 150 ft. to 200 ft. in thickness, well stratified and jointed, divided by narrow layers of more or less marly material in the lower part and by seams of glauconitic material in the higher part, with occasional worm-borings on the top of the hard limestone layers. These borings are filled with marly material in the lower parts and by glauconitic material in the higher parts, corresponding to the character of the layer which was being deposited while the borings were being made. Glauconitic material becomes more pronounced in the higher parts till it passes into the Weka Pass stone, which is here slightly more glauconitic than in the typical locality. The sequence is perfectly conformable throughout, the limestones changing from the Amuri to the Weka Pass facies with characteristic passage beds in which the two types are interstratified along the line of junction. In some places it is difficult to tell the precise line of demarcation of the two. No nodules were seen.

North Side of Waikari Creek between Waikari and Scargill.

On the north side of this stream lies a prominent band of limestone with a west-south-west strike, dipping south-south-east. It is a remnant of a more extensive covering sheet of Tertiary sedimentaries which has been faulted into a position less exposed to destructive agents as a result of earth-movements which have affected the whole region. The main fault-line follows approximately the line of the stream-valley, but a number of subsidiary faults running parallel to this on its northern side are plainly in evidence in the upper basin of the Scargill Creek, where there are a number of parallel belts of limestone, generally dipping south-east, the repetition of the outcrops being directly attributable to this series of faults. The steep scarps face north-west, and they give good opportunities for examining the limestone through its whole thickness. Specially good exposures occur on the north side of the high escarpment behind the greywacke barrier which divides the Scargill basin from the Waikari Valley, and fronting the stripped surface of greywacke which separates the former from the Culverden basin. The section shows that the limestone band is composed of alternating layers of more or less glauconitic material, some of which, usually the less glauconitic, have the jointing characteristic of the Amuri limestone, while

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other layers have the Weka Pass stone facies. Worm-borings are found at various levels, and very occasional nodules are sporadically distributed.

Rock of similar features is to be seen on the north bank of the Waikari Creek about two miles below the Waikari Township. In this place fragments of whale-bone occur in rock of the Weka Pass type.

There is no evidence in either of these localities of any break in the succession, the whole being certainly conformable. Although there is some variation in the lithological character of the rock from that in typical localities, yet there is no reason to suppose that it has not been formerly in close lateral continuity with the masses on the south side of the valley which show the typical differentiation into stone of two facies. There is just the difference that one would anticipate were the beds north of the Waikari deposited in an area in closer proximity to a shore-line than that in which the beds were deposited in the main Waipara, the Weka Pass, or the Cass Range areas. The fact that the sequence is unbroken in what appears to be a shallow-water facies, where one would anticipate breaks, supports the contention that the deeper-water beds are conformable.

Gore Bay.

An interesting locality is Gore Bay, near Cheviot, where sections are well exposed on the cliffs along the shore and on the southern side of the gorge which the Jed River has cut along the line of junction of the grey-wackes and the overlying Cretaceous and Tertiary beds. These latter are bent up into a well-marked syncline, which forms such a characteristic feature of the cliffs behind the sandhills of Gore Bay. Faulting is common, and on the southern wing of the syncline this has resulted in considerable crushing and brecciation along the belt of movement; nevertheless the relations of the beds are clear. The Amuri limestone in its typical facies is somewhat thin in this locality—about 12 ft.; but there is an underlying succession of marls with interstratified sandstone which is no doubt the equivalent of the lower part of the Amuri limestone at Kaikoura and other localities farther north and in the neighbourhood of Weka Pass. The upper surface shows a characteristic junction, with phosphatic nodules, succeeded by a calcareous greensand, the probable equivalent of the Weka Pass stone. (See Hutton, 1885, p. 271, for a similar occurrence near Stony-hurst.) There is no evidence, however, of an unconformity, the sequence throughout being entirely regular. The following is a detailed description of the occurrence in a deep washout in the cliffs about a quarter of a mile north of the disused landing-stage at Port Robinson. The beds are much crushed, but their relations in the vicinity of the line of junction are clear and characteristic. (Plate VI, fig. 1.)

Amuri Limestone.—The typical portion is about 12 ft. thick, but it is underlain by greyish marl. Borings begin about 3 ft. below the upper surface, but they increase in number till the contact is reached. The cavities are filled with greensand.

Nodular Layer.—This is 6 in. to 8 in. thick. The nodules are in a matrix of greensand, some being of phosphatized limestone, the other more characteristic ones varying in colour from light green through olive-green to dark green and black.

Calcareous Greensand.—This is the probable equivalent of the Weka Pass stone. It is strongly calcareous, and contains nodules sporadically up to 3 ft. above the junction. Some of these have the external appearance of greywacke but are distinctly phosphatic, and are dark green in colour. They are up to 2 ½ in. in diameter, but numbers of them are small.

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An exactly similar section occurs on the north wing of one syncline where the road comes down on to the beach near the old lime-kiln. This locality is also noteworthy since the limestone contains abundant nodules of flint. There is no evidence of unconformity. A similar junction occurs on the steep scarp facing the Jed River, but farther north-west, on the south side of the road leading to Cheviot, we were unable to locate it definitely owing to the covering of grass where the loose greensand had been removed; but the borings in the limestone were noted in various places, so no doubt a similar contact exists there as well.

South Bank of the Hurunui.

On the south bank of the Hurunui, half a mile up-stream from the lowest bridge and about a mile from the sea, the whole series from the greywacke upwards is clearly exposed on the river-bluffs. The section consists of the followin:—

(1.)

Sands.

(2.)

Amuri limestone, over 50 ft. thick, with a north-and-south strike, and a westerly dip of 10°. It is of the usual character, the upper 4 ft. perforated with borings, the cavities filled with greensand. Included in the limestone are lenticules of greensand, and in the uppermost 2 ft. this condition is more pronounced, typical green nodules occurring sporadically.

(3.)

Nodular layer: This is 6 in. in thickness, the nodules being dark green to brown in colour, up to 2 in. in diameter, subangular, the whole layer being densely compacted with greensand cement.

(4.)

Calcareous greensand, soft, very glauconitic, and containing nodules scattered through the lower 2 ft.

(5.)

Calcareous greensand, 30 ft. thick. A fragment of coal 3 in. in length and 1 in. thick, lignitic in character, was noticed in this bed.

The section is closed by brown sands. Parts of the section are faulted, but where there is no evident disturbance the conformity is clearly displayed. Especially is this the case on the river-cliffs. In a cutting on the road in close proximity water-worn pebbles of greywacke are apparently involved near the junction, but they also occur in greensand 2 ft. above the junction; the occurrence is only a few feet in length, quite local, and, as the rocks show disturbance, may be attributed to fault or slip movements, since no similar phenomenon was observed elsewhere.

On Coast South of the Blyth River.

This section can be seen near the top of the magnificent limestone cliffs which form the background of the Napenape beach, one of the finest coastal scenes in New Zealand. Here old shore-platforms with beach-gravels on top occur at a height of 500 ft. The sequence exposed is as follows:—

(1.)

Amuri limestone: This strikes north-east, and dips south-east at low angles; it is probably affected by slight local folding, but, owing to slipping, the precise direction is difficult to determine; its thickness is at least 300 ft. The rock is beautifully white, compact in texture, jointed in typical fashion, but much disturbed by slips and faults owing to erosion of the shore and to natural fractures. A small mollusc shell was found in the upper layer, which has been identified by Mr. Suter as a variety of Pecten williamsoni.

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(2.)

Greensand layer: This is loose, calcareous but strongly glauconitic, 8 ft. thick, without nodules as far as could be seen on the face of the steep cliff, and passing up into

(3.)

Glauconitic arenaceous limestone, 12 ft. thick, resembling Weka Pass stone but rather more sandy.

(4.)

Grey marl: This succeeds (3) with perfect conformity. Its thickness cannot be estimated, since the highest shore-platform has been cut in it.

The upper layer of Amuri limestone contains borings filled with greensand, and the marl also contains borings filled with marl.

Stonyhurst, in a Creek near the Homestead.

This place was visited in order to obtain observations of the section recorded by Hutton (1885, p. 271). It is unfortunate that he does not give the precise locality, but a careful examination of the creek in the neighbourhood of the station showed that only one section in the course of the stream was possible, and a description of this is given below. Hutton's remarks are, however, very important. He says, “Here the Amuri limestone is overlain by grey sandstone, probably the representative of the Weka Pass stone. Between the two rocks is a bed of conglomerate formed by sub-angular pebbles of slate. At first sight all three appear to belong to one system, but a close inspection shows that the surface of the limestone is fissured, and that the sandstone penetrates through the conglomerate into the limestone. This, however, may be due to chemical erosion.”

The special importance of these remarks is that they contain a record of pebbles of greywacke along the junction; it is extremely likely that these pebbles are phosphatic nodules, since at times the latter closely resemble greywacke in external appearance. It is unfortunate, therefore, that Hutton's precise locality cannot be determined.

In the creek near the homestead the beds lie very flat, and are obscured by surface accumulations and vegetation. At one place a clear section was seen, the only one occurring in the creek. Its record is as follows:—

(1.)

Typical Amuri limestone, striking north-east, and dipping south-east at an angle of about 25°.

(2.)

Nodular layer, 6 in. thick, with the usual characters.

(3.)

Calcareous greensand. This passes up into

(4.)

Weka Pass stone of more than usually glauconitic character.

The locality is disturbed by faults, but away from the disturbance the dip and strike of the Amuri and greensand limestones are identical.

Motunau River.

An excellent section through the whole series is to be seen in the lower course of the Motunau River, and the limestones are well exposed in its limestone gorge about two miles from the sea. The beds strike here north-north-east, and dip east-south-east at an angle of 20°, the whole being absolutely conformable. The sequence is as follows:—

(1.)

Amuri limestone, with typical macrostructure, its estimated thickness being 300 ft., the upper 4 ft. with borings filled with greensand.

(2.)

Nodular layer, 3 in. to 4 in. thick, composed of subangular nodules in a matrix of greensand; the nodules are up to 3 in. in diameter, dark-blackish-green in colour, with brown shade inside (? Hutton's greywacke pebbles).

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(3.)

Greensand, 25 ft. thick with sporadic nodules in the lowest 2 ft., more thickly distributed near the junction. This passes up with occasional more marly or arenaceous layers into arenaceous limestone (Mount Brown limestone); passage beds are well developed along the junction.

Boundary Creek.

Boundary Creek, which lies midway between Stonyhurst and Motunau, was also examined, since McKay (1881, p. 111) records a good section there. The exposure was found to be very unsatisfactory owing to slips, although probably it was in better condition when McKay described it nearly forty years ago. The Amuri limestone appears to be about 20 ft. thick, but the exact contact with the overlying beds is not visible at present. Large blocks of greensand also occur in the bed of the stream, showing plentiful subangular nodules similar to those in the Motunau, associated with borings filled with greensand, no doubt near the actual junction. McKay does not mention this greensand layer, and says that grey marls immediately overlie the Amuri limestone. Judging by the dip, the limestone is in a conformable position under the top beds of the series, which have a general synclinal arrangement with the eastern limb towards the present coast-line; but there are local variations in dip well displayed on the sides of the deep gorge which the stream has cut through the non-resistant sands and marls which close the Tertiary series in this locality. It is noteworthy that McKay considers the sequence below the Motunau beds to be perfectly conformable, although he places a stratigraphical break immediately at the base of these beds, a conclusion which appears to us not warranted by observations of dip and a general examination of the section both here and in the Motunau River. The similarity of the sections in the two localities is most marked, and the evidence available from one supports that from the other.

South Side of Amuri Bluff. (Plate VI, fig. 2.)

The Amuri limestone is much jointed into flaky quadrangular blocks something like a tiled roof; it strikes north-east, and dips south-east 30°. The top 4 ft. are bored through and through with tubes which are well filled with calcareous greensand, the phenomena being progressively more marked as the upper surface is reached, where the rock is completely honey-combed and the fragments are detached. These are from 1 in. to 3 in. in diameter and are also completely bored. From this level upwards the pebbles decrease in importance and the greensand increases. All through the greensand layer nodules occur, which become smaller in the upper portions; the thickness of the greensand layer is about 2 ft., and the nodular portion where the structure is most marked is about 1 ft. thick. Above the greensand layer the rock passes gradually upward for about 3 ft. into typical Amuri limestone. The nodules of the upper layer are markedly phosphatic, while those of the lower layer are only slightly so; the phosphatization apparently diminishes progressively from the nodular layer. There are numerous sharks' teeth and occasional bones (? whale-bone) in the nodular layer.

On Bluff North of the Mikonui Creek.

The bed is exposed on the face of the cliff immediately to the north of the point where the track rises over the shoulder of the spur to escape high tides. Here we have the following sequence: First, typical Amuri

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Plate VI.
Fig. 1.—Contact of Amuri limestone with greensand layer containing phosphatic nodules, Port Robinson. A small fault is also apparent.
Fig. 2.—Nodular layer in Amuri limestone, south side of Amuri Bluff. The parallelism of the layers is very marked.

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Plate VII.
Fig 1 —Nodular layer in Amuri limestone, Maori village, Kaikoura Peninsula. The dark, flat surface marks a fault almost parallel to the strike.
Fig. 2.—Nodular layer in Amuri limestone, Atiu Point, Kaikoura Peninsula. Note the parallelism of the beds

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limestone, followed by greensand with inclusions of Amuri limestone, 5 ft. thick in one place, and containing distinctly angular, black phosphatic pebbles. In some parts of the contact the Amuri limestone has inclusions of greensand, the latter being in relatively small amount. This is succeeded by 12 in. of nodular layer of the usual type, and followed then by glauconitic limestone with small green nodules and black nodules. As the band is traced north and south from the point under consideration the greensand is not so prominent but is mixed with Amuri limestone, which is especially glauconitic on or near the junction.

Near Maori Village on South Side of Kaikoura Peninsula. (Plate VII, fig. 1.)

The contact is well exposed in this locality on the raised shore-platform which covers a large area on the south side of the peninsula. The following sequence in ascending order occurs here:—

(1.)

Amuri limestone, of the usual type, but rather more flaky than jointed, perhaps the effect of faulting.

(2.)

Fault, almost parallel with the strike, with a small but increasing throw when followed to the south-west.

(3.)

Calcareous greensand from 8 in to 10 in. thick, showing honey-combed borings filled with glauconitic limestone, together with masses of greensand of irregular form. The lower part is filled with cavities, some of the worm-bored type, while others are much larger and irregular in form, the whole being filled with a uniform type of calcareous greensand. In the upper portion the worm-casts and greensand masses are smaller.

(4.)

Nodular layer: The nodules are green and black, and the structure is very well developed, so that the intervening spaces are small. These are filled with calcareous greensand.

(5.)

Glauconitic limestone, 4 in. to 5 in. thick.

(6.)

Greensand, ½ in. thick.

(7.)

Glauconitic limestone, rather more glauconitic than (5), 5 in.

(8.)

Greensand, 1 in.

(9.)

Glauconitic limestone, more glauconitic in the lower layer but passing up into one which is less glauconitic, 10 in.

(10.)

Limestone, of Amuri type, with flints, 6 in.

(11.)

Glauconitic limestone, with only a small amount of glauconite.

(12.)

Amuri limestone as typically developed, 120 ft. in thickness.

This section shows no sign of unconformity.

North of Atiu Point, East End of Kaikoura Peninsula. (Plate VII, fig. 2.)

The contact is well displayed in this locality on the shore-platform at the base of the cliffs and on the cliffs themselves. The following is a description of the beds in immediate proximity to the contact:—

(1.)

Amuri limestone.

(2.)

Calcareous greensand: The rock is bored in the usual manner and the interstices filled with calcareous greensand, and becomes more glauconitic upwards, and contains nodules green in colour, irregular in shape, up to ½ in. in diameter. This merges gradually into the nodular layer.

(3.)

Nodular layer, consisting of phosphatic nodules, more continuous than usual, the progressive development being more marked, the nodules being in a cement of calcareous greensand.

(4.)

Limestone, 2 ½ in. thick, with nodules in small number.

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(5.)

Calcareous greensand, 2 ½ in. thick, well bedded.

(6.)

Glauconitic limestone, 8 in.

(7.)

Greensand, 3 in.

Above this there are regularly distributed layers of calcareous greensand and glauconitic limestone throughout the next 3 ft. above the nodular layer, and this is followed by

(8.)

Amuri limestone, with flints, the lower 10 ft. of which is bedded in layers which are more or less glauconitic, which finally passes up into typical stone striking north-west, and dipping south-west 10–15°.

All the layers of this sequence are much folded, the intensity of the deformation being of the same order in each case.

The same beds are seen on two other cliffs north of Atiu Point where the strata strike almost parallel to the shore-line but with acute minor folding. The nodular bed is 8 in. to 10 in. thick, with the same general features as before; the greensand layers are, however, between thicker beds of limestone above, but underneath are the same as usual.

The nodular layer also occurs on the shore-platform in this locality, but is much contorted and separated by faulting from the main layer.

North Side of Kaikoura Peninsula, on the Shore-platform between the Old and New Wharves.

This occurrence has not been noted previously, as it is somewhat difficult to locate. The limestone in which it occurs is much folded and contorted, but where the contact occurs the strike is north-east, and the dip south-east at an angle of 50°. The following is the sequence as here shown:—

(1.)

Amuri limestone, flaky in general, but subschistose occasionally owing to the movements of the beds, and with crystalline texture. The upper 6 in. of the limestone contains a considerable amount of flint, some of which contains calcareous greensand in borings, an extremely important point bearing on the origin of the flint.

(2.)

Nodular layer, 6 in. thick, with nodules in a glauconitic matrix but less rich in nodules than usual, and succeeded by

(3.)

Glauconitic limestone and calcareous greensand in alternate layers, the former 3 in. and the latter ½ in. in thickness. The lowest 3 ft. contain small and typical green phosphatic nodules. Thereafter the layers of glauconitic limestone are thicker, but still alternate with narrow bands of calcareous greensand to a depth of 20 ft. to 25 ft. It should be noted that at one spot three angular pebbles of basalt 2 ½ in. in diameter were found. These may have been of contemporaneous origin, but more likely were embedded at a later date, as others were found loose.

Mouth of Lyell Creek, Kaikoura.

The contact of the typical Amuri limestone with the overlying stone of the Weka Pass facies is to be seen close to the mouth of Lyell Creek on the northern side of the Kaikoura Peninsula. It is on the western wing of the anticline which forms the main mass of the peninsula. The beds strike here east-north-east, and dip north-north-west at an angle of 20°, the agreement between the two facies of the rock being complete.

The following is a description of the contact as far as it can be seen; at the time of our visit it was unfortunately partly obscured by a covering of beach shingle.

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The underlying beds are of Amuri limestone as typically developed, very white, with flaky jointing and nodules and masses of flint, and with borings filled with greensand. Over this lies, with the intervening beds obscured by gravel, a glauconitic limestone, with inclusions of Amuri limestone which is decidedly phosphatic, the thickness being uncertain but certainly not more than 3 ft., the upper portion containing more of these than the lower part. It is succeeded without any unconformity by a much more glauconitic limestone—in fact, a greensand—from 6 in. to 8 in. thick, containing borings, and also small, dark, oxidized nodules. This is followed by a glauconitic limestone, also with nodules, which become smaller and smaller in the higher levels. The glauconitic character is very marked, with a concentration of the glauconitic material in well-defined layers; and borings filled with more highly glauconitic material occur throughout the whole thickness of the bed. This is succeeded in about 30 ft. (?) by the ordinary type of Amuri limestone, which very occasional glauconitic layers. No flint was observed in the upper part of the limestone. The whole section is strongly reminiscent of that at Weka Pass.

Puhipuhi Valley and Long Creek.

The limestone up the Puhipuhi Valley and that occurring up Long Creek on the southern side of the Hapuku River were also examined in order to see if any similar horizon occurs marked with phosphatic nodules, but with unsatisfactory results. The best exposure that was encountered was in a cutting just past the bridge over the Clinton River, a similar junction, somewhat obscured, being observed in the gorge of the Clinton River itself. The beds in this locality are much folded, and have suffered crushing as a result of folding and faulting movements, so that their stratigraphy is not clear. In the road-cutting to the north of the bridge the beds strike east-north-east, and dip north-north-west at an angle of 60°. The ordinary Amuri limestone is succeeded by layers of calcareous greensand, the layers being more or less glauconitic through about 15 ft., some being distinctly greensand. This is succeeded by hard greyish-green arenaceous limestone, well jointed, and with bands of more greenish tint running through it. It is much crumpled and faulted, and at least 70 ft. thick, and passes up into layers of more arenaceous character. This limestone is decidedly phosphatic. There is a strong similarity to the beds exposed some ten miles away at Lyell Creek, but no nodules of phosphatic nature were met with. Although they are apparently absent, it seems quite reasonable to maintain that the junction is on the same horizon. There is no evidence of unconformity.

Contact of the Grey Marl with the Underlying Limestone.

Although discussion of this contact is not directly connected with the principal subject of this paper, it has some bearing on the question, and therefore a description of all the contacts noted is here included. As the grey marl is easily eroded and apt to weather readily into soil, good exposures are rare. Those examined, however, show certain features which resemble the contact of the Amuri limestone and the Weka Pass stone, notably the bored upper surface of the limestone and the presence of detached fragments of the lower layer included in the higher, and it seems reasonable that if unconformity is demanded in one case it must also be demanded in the other. A consideration of the following sections will illustrate our contention as to similarity of evidence.

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Main Branch of Weka Creek.

This section occurs in the main branch of Weka Creek, below the small bridge on the road from Weka Pass in the direction of the Waipara River to the north-west of the Deans Range. The junction between the Weka Pass stone and the overlying marl is well seen in the bed of the creek and on the sides of the deep but narrow gorge where the road crosses. The agreement in dip is absolute, and the contact does not show any signs of unconformity. The Weka Pass stone exhibits on its upper surface the same kind of borings which mark the contact of the two limestones, but the bored zone is narrower. This is succeeded by 1 ft. of slightly glauconitic sandy marl, then by 12 ft. of slightly glauconitic sandstone, passing up into sandy marl and becoming more argillaceous higher up but still preserving something of its arenaceous nature.

Near Old Wharf, North Side of Kaikoura Peninsula.

The upper surface of the Amuri limestone is tily in character, as at Amuri Bluff, with lenticules of grey marl included in the limestone, as also there are inclusions of limestone in the grey marl, the inclusions being more phosphatic than the limestone and marl in general, which are practically free from phosphate. The marl is decidedly glauconitic near the contact, and presents all the features of a fine-grained glauconitic sandstone, the sandy facies extending for 10 ft. or 12 ft. above the contact. The contact is conformable stratigraphically, any divergence from a normal junction being due to folding or faulting.

East Side of Kaikoura Peninsula.

The general strike of the beds is north-east. The Amuri limestone is much contorted, brecciated by folding, faulted, and, as a result of these structural movements, crystalline in many parts and at times subschistose in appearance. The grey marl is folded on the same lines, and sometimes included in the limestone as a result of folding. The grey marl has been subjected to just the same intensity of deformational movement as the limestone, but it exhibits the results of these movements to a much smaller degree except at the immediate contact with the limestone, where it is subschistose in structure. The whole locality exhibits faulting, some of the major faults running north-north-east parallel to the general trend of the coast-line of the Island, but there are numerous others crossing at right angles, so that the whole locality may be described as a complex of faulted anticlinoria and synclinoria, but wherever the junction between the marl and the limestone is clear the junction is conformable. It might be noted here that Hutton's figure of the East Head (1885, p. 273) is entirely incorrect.

On the south side of the peninsula, near the Maori village, the contact is of the same character as on the north side. The Amuri limestone is slightly glauconitic, becoming more so near the junction. There is a layer about 6 in. thick where the limestone and the marl are mixed, a phenomenon which is in part due to boring. The grey marl is glauconitic in its lower part for a thickness of several feet, and contains numerous fragments of whale-bone. Along the line of contact faulting is much in evidence, the faults being both normal and reversed, with a direction in general at right angles to the strike. The figure by Hutton (1885, p. 273) is evidently given under a misapprehension of the effects of faulting, the irregular line of contact being attributed by him to erosion.

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South Side of Amuri Bluff.

In this locality the sequence is well exposed on the finely developed shore-platform, on the south side of the bluff and around the coast-line as far as the mouth of the Okarahia Creek. Above the nodular layer there is about 15 ft. or so of limestone, and this is succeeded conformably by a greenish calcareous sandstone, perhaps the equivalent of the lower part of the typical grey marl, or perhaps, as is more likely, the equivalent of the Weka Pass stone. The upper portion passes into a typical marl of decidedly argillaceous character. Hutton considered that this locality furnished strong evidence of unconformity between the grey marl and the Amuri limestone, his main line of evidence being the discordance in the dip of the former as it occurs in the neighbourhood of the mouth of the Okarahia Creek and south of it with the limestone at the bluff. This apparent discrepancy in angle of dip is due to folding and twisting movements affecting the beds unequally in the two localities. The limestone south of the creek dips at a very high angle, and the marl is in perfect accord with this; while when traced in a north-easterly direction towards the bluff the beds flatten out, and nowhere present any evidence of discordance.

Evidence That The Series Is Conformable.

This detailed account of the sections taken from widely separated parts of the area gives some idea of the general nature of the contact and emphasizes the similarity of its features. Relying entirely on the evidence of the borings in the upper surface of the Amuri limestone and the presence of detached fragments of the limestone in the greensand matrix of the nodular layer, Hutton and Morgan came to the conclusion that it was a true erosion surface, the supposition being that the erosion took place in the vicinity of a shore-line. No palaeontological evidence was advanced by either in support of their contention as regards the two limestones, the reason being that they are both, the Amuri limestone especially, according to Hutton, almost unfossiliferous; thus in their opinion the existence of an unconformity rests entirely on stratigraphical evidence. We, however, relying on stratigraphical evidence, have come to a conclusion that the sequence is conformable, the reasons for this conclusion being as follows:—

1.

In every case there is absolute agreement in the dip of the beds above and below the nodular layer. When this occurs over a region of a hundred miles in length by some fifteen in breadth, unconformity appears extremely doubtful. It means that a limestone has been laid down on a deep-sea bottom, the rock has become consolidated, raised above the sea, eroded, and again depressed into deep water so that another layer of calcareous material may be deposited, and all this without any variation in angle due to structural movements or to conditions of deposition over hundreds of square miles. Such a contention appears unreasonable.

2.

Apart from the evidence furnished by the included fragments of limestone in the nodular layer, and the report of the occurrence of pebbles of greywacke at Stonyhurst, which can be explained as probably the result of mistaken identification, there is no evidence of erosion of the upper surface of Amuri limestone. On any present-day surface of Amuri limestone there are distinct irregularities, and especially is this the case on the shore-platforms where tidal channels, & c., are a marked feature, and none of these are to be seen at any part of the contact, although it is exposed for many miles in different parts of the area, not only parallel but at right angles to

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the present shore-line. It would be expected that they should occur somewhere. Present-day shore-lines show surfaces of Amuri limestone with no similarity whatsoever to those associated with the nodular layer, even when those parts of the shore-platform are composed of nearly horizontal layers. Any change in the nature of the rocks due to folding and consequent induration which might be cited from the Kaikoura neighbourhood as modifying the conditions would not apply farther south, where the influence of such movements has been comparatively slight.

3.

There is no true shore or shallow-water deposit of any kind over the whole area. It is certain that during the depression demanded by the unconformists, when the surface of the Amuri limestone was lowered from forming part of a land surface or a shore-line to such a level that glauconitic limestone and greensand were deposited, beach and shallowwater beds would occur in some parts of the area. Nevertheless they are absent entirely.

4.

In many places is it impossible to determine the dividing plane between the two limestones, so gradual is the transition—that is, they furnish in some places no evidence of a break. In fact, as a general rule the upper and lower layers display such a similarity in their characters, notably in the presence of glauconite, that transitional forms are to be expected.

5.

In the case of the borings in the upper surface of the Amuri limestone, and also those in the Weka Pass stone in contact with the grey marl, the borings are filled with the material of the overlying bed, however deep they are down below the surface. If this is a greensand the tubes are filled with greensand, if a marl they are filled with marl. Also, there are cases of tubes in the body of the limestone which are filled with the material being laid down on the surface into which the borings were made. If, now, these borings were made on an ordinary beach or shore-platform they would be filled with beach deposit, and would not remain open till they were depressed to a depth at which limestone or greensand was the characteristic deposit.

6.

The remarkable uniformity in the thickness of the layer over long distances appears to be inexplicable on the basis of its being a shore-line deposit, since these are notably variable both in thickness and in the nature of their constituents. The parallelism of the upper and lower surfaces of the layer is well brought out in the photographs taken from various widely separated localities where the bed is well and clearly exposed.

7.

The analyses of the so-called “rolled pebbles” at the junction between the two layers (see page 71) shows that they are not ordinary detached fragments of Amuri limestone such as would be found on a beach, which should resemble the parent rock in chemical composition. They have certainly been modified by agencies other than those operating on a shore-line.

Morgan (1915, p. 92) cites a paper by Edward M. Kindle on “The Unconformity at the Base of the Onondaga Limestone in New York, and its Equivalent West of Buffalo”;* and remarks, “This paper describes fully an unconformity not easily detected at all points by stratigraphical evidence alone.” He uses it to emphasize the fact that an unconformity can occur between two limestones. But it seems to us that such contacts are by no means unlikely, since limestones of various ages form a notable feature of the rocks of the earth's crust, and the probability of a contact between two limestones as compared with that between limestone and

[Footnote] * Joura. Geol., vol. 21, pp. 301–19, 1913.

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another rock of different lithological composition is in proportion as these rocks form part of the earth's crust in the locality where the limestones are being laid down. The criteria of unconformity in general, apart from the possibility of chemical erosion on the plane of contact, will be the same as between limestone and another rock. In Kindle's paper attention is drawn to the difference in dip of the two limestones in question, and to the decided surfaces of erosion of the lower limestone. The photographs that he uses to illustrate his paper are quite convincing, and show pronounced differences in the contact as compared with that between the Weka Pass and Amuri limestones, and we have seen no locality where similar pictures could be obtained from the contact of the two New Zealand rocks.

For the reasons given above the authors consider that the contact between the two limestones is not due to erosion, and that after the deposit of the lower bed no emergence from the sea took place before the second limestone was deposited. Some alteration in depth or in the conditions of deposition no doubt occurred, but they were of no greater amount than that which takes place when a bed of different lithological character is laid down in a perfectly conformable sequence.

It has been pointed out that both above and below the nodular layer there is an interstratification of greensand in the limestone, the deposition being conformable, which shows that slight oscillations of level or conditions took place. The phosphatic nodules are exactly analogous to those forming now on ocean-bottoms at depths of over 100 fathoms in association with greensand, and such do not form on a shore-line. Such nodules are frequently found in the Cretaceous limestones of Europe and America without an unconformity being demanded, although some lapse of time and change of conditions must have occurred. The phosphate nodules occurring in the Cretaceous beds of the south of England and the north of France and in Belgium usually lie at the base of the series which succeeds another after some lapse of time. In some cases, however, distinct unconformity has been demonstrated on account of the presence of pebbles and rolled fossils, the break being of more decided character and amounting to an unconformity, but in other cases there is no pronounced break.

The association of these nodules with a bored surface seems to indicate clearly that the boring took place not on a shore-line, but on a sea-bottom formed of a soft calcareous ooze before it had consolidated and hardened into rock. The borings extend to such a depth beneath the surface that it may be doubted whether it is possible for marine organisms to tunnel such a distance into hard rock, whereas if it be admitted that the boring took place before the rock had consolidated and while it was actually in process of deposition there is no difficulty. The filling of these deep tunnels with greensand, as has been pointed out, certainly suggests boring on a seabottom. Although many marine organisms have the power of making burrows, it occurred to us that they were in all probability made by marine worms, and therefore we applied to Dr. Benham for his opinion on the matter. In a private letter he says, “Unfortunately we know nothing, so far as I can find out from monographs on the Polychaeta, & c., about the burrows in deep water. When the dredge is used the surface of the mud, & c., will still be disturbed; and even if the worms are captured the walls of the burrows, if any, will fall in, and the burrow, of course, will be smashed. So that I find no reference at all to burrows of worms living beyond the littoralzone area. But we may expect that if they are formed at these greater depths they, too, will be U-shaped. You ask at what depths worms live

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and work. Certain species have been found at as great a depth as 3 000 fathoms, though at depths below 1,000 fathoms they are much rarer than at less than 100 fathoms—that is, the great majority live along the continental shelf, and especially along the littoral area.”

This opinion is not conclusive, but it certainly indicates that it is possible for worms to produce borings at the depth at which greensand is deposited.

The statements of Cayeux (1897, pp. 431–32 and 532–33) are of interest in their bearing on this point. He shows that phosphatic nodules occur in ths chalk of France and Belgium at levels marked by change in the depth of the sea, whether this be in the direction of increasing or of lessening depth—that is, they occur at the points of inflexion of the curves indicating the depths of the sea over the area at any particular time. He says (p. 431), “La production du phosphate de chaux de la base de la craie è Belemnitelles correspond è une rupture d'équilibre de la mer crétacée, phénoméne dont on a maintes preuves.” These are then given, and among them may be noted the hardening of the upper layer of chalk and the presence of perforations. The first of these is perhaps analogous to the hardening of the fragments in the upper layer of Amuri limestone which may be attributed to phosphatization, and the second is a most characteristic feature of its upper surface. Farther on (p. 432), he says, “La craie phosphatée du department du Nord est en relation avec un mouvement d'exhaussement qui a eu pour résultat de chasser la mer du golfe du Mons. Son existence est liée è une période de régression de la mer pour le Nord.” Of the two instances quoted, the former applies to an increase in depth of the sea and the latter to a diminution in depth. The latter in all probability is analogous to the change from Amuri limestone to calcareous greensand which characterizes the level of phosphatic nodules in the New Zealand area.

Further, Cayeux considered that the accumulations of phosphatic material took place at such a distance from the shore that the change in depth of the sea did not permit of any marked variation in the character of the terrigenous material associated with the chalk. This is borne out to some extent in the area under consideration, as it has been shown that the material of the phosphate nodules is not markedly different from that of the beds with which they are associated. In any case, Cayeux does not postulate any emergence of the sea-bottom to account for phenomena which are quite analogous to those near the junction of the Amuri and Weka Pass limestones.

The Peculiarities Of The Junction Of The Amuri Limestone And Weka Pass Stone.

It must be admitted that the junction of the Amuri and Weka Pass limestones is a peculiar one and demands some special explanation, seeing that unconformity is not admitted. The irregularity of the junction in some places could be attributed to chemical erosion, and the increased amount of phosphate in the detached pieces of Amuri limestone in the nodular band supports this contention; but it may be explained in another way, or perhaps the two explanations are not mutually exclusive. It seems to us that the so-called erosion surface has been the result of extensive boring during the interval between the deposition of the typical Amuri limestone and the upper more glauconitic part of the bed when it formed part of a sea-bottom. As a result of the complete penetration by borings the upper surface consists in places of peninsulas of limestone surrounded by green-

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sand. In places, too, these jutting portions have been completely cut off, so that they become detached fragments. Similar occurrences can be seen at times in the estuaries which are filled with calcareous mud and have been completely honeycombed by borrowing molluscs, & c. In this way an apparent erosion surface can be formed; but the character of the junction under consideration requires a uniformity of conditions over wide areas, and this would be obtained if the bored surface were a sea-bottom and not a shore-line. The increased phosphatization of the fragments of Amuri limestone, and perhaps of the true phosphatic nodules, might be accounted for by the decay of the bodies of the boring organisms, in addition to probable increased phosphatization owing to concentration by the dissolving-out of the more soluble calcium carbonate from the rock.

The remarkable persistence of the nodules of phosphatic material at a limited level in the limestone renders them extremely useful as a datumlevel for comparing the relative age of rocks in the series, and this is all the more valuable owing to the comparative absence of fossils. It may, of course, be suggested that there is more than one layer in the limestone, and that the phosphatic nodules at Kaikoura occupy a different position from those at the Weka Pass; but the whole of the attendant circumstances of the surrounding beds renders it extremely likely that only one layer exists. If the nodules had been laid down on the bed of a deep sea, then it is likely that the sea extended all over the area in question, and their synchronous formation would be very probable indeed.

Assuming that this is so, it would clearly indicate that the Weka Pass stone was the equivalent of the upper part of the Amuri limestone in the Kaikoura district and also at Amuri Bluff; but, seeing that the lower portion of the grey marl at Kaikoura and Amuri Bluff is lithologically a calcareous greensand, it is not at all improbable that Hutton was partly correct in correlating the Weka Pass stone with the grey marl, only that it is the lower portions of the marl that are equivalent to the upper layers of the Weka Pass stone. However, between the marl and the limestone in the Kaikoura region there is a junction which is analogous to that between the two limestones, in that the limestone immediately below the lowest layer of the grey marl is bored and sporadic phosphatic nodules occur in it. This, of course, indicates some break in time.

At the Amuri Bluff the thickness of the limestone above the nodular band is reduced to 15 ft. as compared with a thickness of 100 ft. or more at Kaikoura and a great thickness as exposed on the sea-cliffs between the Oaro and Mikonui Creeks. It must be mentioned, however, that as the beds are traced along the coast south of Amuri Bluff towards the Conway River they thin out and the limestones lose their distinctive features. This certainly suggests the vicinity of a shore-line, and therefore there is no improbability that the lower part of the grey marl in that neighbourhood, especially that part with sandy texture, may be the stratigraphical equivalent of the glauconitic facies of the Amuri limestone farther north, the sea evidently deepening in a northerly direction. It is probable that an easterly extension of the land, either continuous or in the form of islands, divided the Kaikoura part of the sea from that south of the Hurunui. The existence of such a land if it were of low relief would not, of course, negative the contention that a sea extended generally over the site of the present Kaikouras, and that the land had been base-levelled to some extent before being depressed and covered with a veneer of Tertiary sediments. But it must be clearly understood that the shore-lines of this land must not be con-

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sidered as related to the present orographic features. These are, no doubt, a very late development, as demanded by McKay and by Cotton. The failure to appreciate this point thoroughly no doubt influenced Hutton, and to some extent Morgan (1916, p. 28), in attempting to fix the position of the shore-line of the Tertiary sea in that region.

Since we maintain the conformity of the two limestones, and since we can suggest no other horizon where a physical break occurs in the series under consideration, our present contention involves the recognition of the stratigraphical conformity of beds in the lower part of the sequence containing Cretaceous fossils with those higher containing Tertiary fossils. (For the latest pronouncement on the Cretaceous age of the lower members of the series see Trechmann, 1917, p. 295.) In our opinion the beds with Cretaceous fossils are definitely Cretaceous, and those higher up with Tertiary forms are Tertiary. The anomaly is accounted for by the slow and continuous deposition of the beds, so that when the period of deposition commenced the time was Cretaceous, and when it closed it was Tertiary, judging by European standards of geological time. The earlier part of this period was marked by slow depression of the land, with a corresponding change in the nature of the deposits (see Speight, 1917, pp. 350–51). During the time of maximum submergence the greensands and limestones were deposited, and as the sea-bottom was raised a reversal of the order took place with slight minor oscillations. When one considers the small area of land which was probably in existence above sea-level in the vicinity of the region under consideration, the slow rate of deposition can be readily understood. Thus during this long period of submergence of the area the local fauna had time to change from a Cretaceous to a Tertiary facies.

Bibliography.

Cayeux, L., 1897. Terrains sédementaires, Memoires de la Société géologique du Nord, Tome IV.

Cotton, C. A., 1912. Typical Sections showing the Junction of the Amuri Limestone and Weka Pass Stone at Weka Pass, Proc. N.Z. Inst., pp. 84–85.

Haast, J., 1871. Rep. Geol. Explor. dur. 1870–71, pp. 15, 25.

Haast, J. Von, 1879. The Geology of Canterbury and Westland, p. 297–98.

Hector, J., 1869. Rep. Geol. Explor. dur. 1868–69, p. xii.

Hutton, F. W., 1877. Rep. Geol. Explor. dur. 1873–74. p. 27.

—— 1885. The Geological Position of the Weka Pass, Stone, Quart. Journ. Geol. Soc., vol. 41, pp. 266–78.

—— 1888. On Some Railway Cuttings in Weka Pass, Trans. N.Z. Inst., vol. 20, pp. 257–63.

McKay, A., 1877. Rep. Geol. Explor. dur. 1874–76, p. 36.

McKay, A., 1881. Rep. Geol. Explor. dur. 1879–80, pp. 108–17.

—— 1886. Rep. Geol. Explor. dur. 1885, p. 27.

—— 1887. Rep. Geol. Explor. dur. 1886–87, pp. 74, 78.

—— 1890. Rep. Geol. Explor. dur. 1888–89, p. 85.

Marshall, P., 1911. New Zealand and Adjacent Islands, Handbuch der regionalen Geologie, pp. 22–26, 39–41.

—— 1912. The Younger Rock Series in New Zealand, Geol. Mag. (n.s.), dec. 5, vol. 9, p. 314.

—— 1916. The Younger Limestones of New Zealand, Trans. N.Z. Inst., vol. 48, pp. 87–99.

—— 1916A. Relations between Cretaceous and Tertiary Rocks, Trans. N.Z. Inst., vol. 48, pp. 100–19.

Marshall, P., Speight, R., and Cotton, C. A., 1911. The Younger Rock Series of New Zealand, Trans. N.Z. Inst., vol. 43, pp. 378–407.

Morgan, P. G., 1915. Weka Pass District, North Canterbury, 9th Ann. Rep. (n.s.) N.Z. Geol. Surv., Parl. Paper C.-2, pp. 90–93.

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Morgan, P. G., 1916. Notes on a Visit to Marlborough and North Canterbury, with Especial Reference to Unconformities post-dating the Amuri Limestone, 10th Ann. Rep. (n.s.) N.Z. Geol. Surv., Parl. Paper C.-2B, pp. 17–28.

—— 1916A. Record of Unconformities from Late Cretaceous to Early Miocene in New Zealand, Trans. N.Z. Inst., vol. 48, pp. 1–18.

Park, J., 1888. Rep. Geol. Explor. dur. 1887–88, p. 25–35.

—— 1905. Marine Tertiaries of Otago and Canterbury, Trans. N.Z. Inst., vol. 38, p. 546.

—— 1910. The Geology of New Zealand.

—— 1911. The Unconformable Relationship of the Lower Tertiaries and Upper Cretaceous of New Zealand, Geol. Mag. (n.s.), dec. 5, vol. 8, pp. 539–49.

—— 1912. The Supposed Cretaceo-Tertiary Succession of New Zealand, Geol. Mag. (n.s.), dec. 5, vol. 9, p. 314.

Speight, R., 1912. A Preliminary Account of the Lower Waipara Gorge, Trans. N.Z. Inst., vol. 44, p. 221.

—— 1915. The Intermontane Basins of Canterbury, Trans. N.Z. Inst., vol. 47, p. 336.

—— 1917. The Stratigraphy of the Tertiary Beds of the Castle Hill or Trelissick Basin, Trans. N.Z. Inst., vol. 49, pp. 321–56.

Thomson, J. A., 1912. Field-work in East Marlborough and North Canterbury, 6th Ann. Rep. (n.s.) N.Z. Geol. Surv., pp. 7–9.

—— 1916. The Flint-beds associated with the Amuri Limestone of Marlborough, Trans. N.Z. Inst., vol. 48, pp. 48–58.

Trechmann, C. T., 1917. Cretaceous Mollusca from New Zealand, Geol. Mag. (n.s.), dec. 6, vol. 4, pp. 294–305, 337–42.

Art. VI.—Structural and Glacial Features of the Hurunui Valley.

[Read before the Philosophical Institute of Canterbury, 5th December, 1917; received by Editors, 31st December, 1917; issued separately, 24th May, 1918.]

The Hurunui Valley is one about which little has been said in geological literature, though it is one of the most interesting of the main river-valleys of Canterbury, not only for its structural pecularities, but also for the glacial features of the country in the vicinity of its headwaters. The comparative neglect is perhaps due to the relative inaccessibility of its higher parts owing to the absence of roads, though before the discovery of Arthur's Pass it was the recognized route from Canterbury to Westland, while the lower portions were, till the opening of the Cheviot Settlement and the completion of the Waipara-Cheviot Railway, quite off the main lines of communication.

In 1865 Haast made a journey up the river across the island, an account of which is given in his Geology of Canterbury and Westland (1879), including a general description of the chief landscape features of the upper part of the basin. In 1871 he visited the middle Hurunui, and furnished a report (1871), in which he referred to the basin of the Mandamus, the main northern tributary of the Hurunui. Hutton (1877, pp. 34, 35; 1889) also gave some account of the locality, and dealt with the origin of the Hurunui Plains (1877, pp. 55, 56). This is practically all that has been written on the features of the main valley, except a brief reference by myself (1915, pp. 347–48) to the formation of the Waiau-Hurunui intermontane basin. Of course, there is abundant reference to the country to the north and south of the river, such as the Pahau Valley, and to the interesting stratigraphical questions connected with the Waikari and Greta Valleys, but a consideration of these is foreign to the scope of this paper. It is intended to give an account of the general geology of the basin only in so far as it is connected with its peculiar structural and glacial features.

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General Topography.
(See map, fig. 1.)

The chief stream of the Hurunui rises in the main chain of the Southern Alps, and flows east between bush-clad mountains whose height approximates between 5,000 ft. and 6,000 ft. till after a straight course of some eighteen miles it empties into Lake Sumner. This is a fine lake, seven miles long by one a half wide in its widest part, 1,724 ft. above sea-level. Thence the Hurunui flows south-east for about eight miles, and receives on the south a tributary almost as large as itself, called the South Branch, the main stream being sometimes called the North Branch. In this part of its basin are several small lakes, the most important being Lake Katrine (which is practically an indentation near the head of Lake Sumner), Lakes Taylor (1,914 ft.) and Sheppard (1,916 ft.) in a valley between the two branches, and Lake Mason in a side valley of the South Branch.

Below the junction of the two main streams the valley continues for nearly three miles in a south-easterly direction between somewhat precipitous mountain-sides, and then turns east and passes through a deep, narrow, picturesque gorge, locally known as Maori Gully, and believed to be the scene of an engagement between two Maori tribes in early days.

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Fig. 1.—The Hurunui Valley.

The river then flows north-east for nearly ten miles through a hilly region in a narrow channel cut in the floors of detached basins and deeply incised in the ridges dividing them, till it reaches the Mandamus River.

Just below the junction with this stream the direction of the main river turns through a right angle and it enters the Hurunui-Waiau basin, flowing for about ten miles through an aggraded flood-plain till it receives the Waitohi on the south. It then makes a sudden turn and runs north-east along the southern edge of the Hurinui Plain, receiving the Pahau River on the north; but after a course of about eight miles it again breaks through a mountain barrier in a south-easterly direction and receives the Waikari River on the south and the Kaiwara Creek on the north, immediately after which it breaks through yet another mountain barrier and debouches into the Greta-Cheviot basin, across which it flows in a broad bed with terraced banks in an easterly direction till it discharges into the sea after cutting a somewhat deep gorge through a rocky bar just at its mouth.

The most striking feature of its course as a whole is the peculiar zigzag direction of the reaches which characterizes the middle part of its basin. These zigzags have alternate north-west and south-east and south-west and north-east arms, and it is their special relation to the grain of the country in some places and their absence of relation in others which is peculiar.

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Basement Rocks Of The Area.

The characteristic basement rock of the region is a greywacke such as is typically developed in the mountains of Canterbury farther south. This is usually of the hard grey facies, but slaty greywackes also freely occur, which break down under the weathering agencies into clay and form a covering on the mountain-slopes. On these forest once became thoroughly established, but it has been largely destroyed in the higher parts of the river-valley by the grass fires of settlers. The greywackes have a general north-easterly strike, with local variations. Beds of dark-red slaty shale also occur, as well as occasional outcrops of volcanic rock. Basalts and andesites occur near Lake Sumner on the Crawford Range, and there is in the Canterbury Museum a specimen from the same area marked “eurite” by Hutton. Basalt pebbles occur in the Seaward River, a tributary coming in from the south about three miles below the junction of the two branches, and similar rocks occur in position between it and the Waitohi River.

The most interesting occurrence is near the Mandamus. About a mile above its junction with the main stream a massive intrusion of augite syenite occurs in the greywacke. This has a general north-easterly trend, and it appears to have the character of a sill, being approximately parallel to the dip and strike. Its thickness is more than 200 ft., and it extends over a mile in length. Associated with it are trachyte dykes, and flows of augite andesite occur in close proximity. Hutton was of the opinion that the syenite represented the core of a volcano of which the andesite was the effusive representative. But angular fragments of the syenite are found in the andesite, in some places in considerable quantity, so that the intrusion of the syenite was evidently anterior to the andesite. We have therefore, in order of time, (1) greywacke, (2) syenite, and (3) andesites. In this district, too, there are basic volcanic tuffs having in their higher levels a calcareous tufa facies passing into a true limestone; but the volcanic beds are much better developed to the north-east, in the Pahau and Culverden districts, where there are interstratifications of volcanic material between beds of limestone. The occurrence at the Mandamus points to several periods of vulcanicity, the channel opened by the syenite affording a passage for later magmas.

Younger Rocks.

Volcanic rocks have exerted little effect on the area covered by the river basin, in which greywacke is now by far the most dominant member; but at one time the lower parts of the valley were covered with a veneer of Tertiary sediments, remnants of which are still to be found. These later beds have all a north-easterly strike, so that they cut across the river at a average angle of 450, and at present they occupy separate compartments of the valley, cut off from adjacent ones by ridges of greywacke. These isolated areas are as follows: (1) In the Dove River, a tributary of the Mandamus coming in on the east; (2) in the Hurunui-Waiau basin; (3) in the Waikari-Kaiwara basin, or rather trench; (4) in the Greta-Cheviot basin. The special features of these may be taken in turn.

(1.) The Dove River Area.

The Dove River basin is important, not from its size, but because it gives an indication of the origin of the landscape features of a considerable area of hill country forming a kind of platform or terrace at the base of the

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higher region to the north-west. The Tertiary beds here consist of the following:—

4.

Limestone, passing down into

3.

Calcareous breccia with volcanic fragments.

2.

Volcanic tuffs and ash-beds.

1.

Sands with concretionary layers.

The lower parts of these probably contain coal, seeing that an adjacent stream is called Coal Creek. (See also Haast, 1871, p. 30.) The limestone is crystalline in texture, but shows traces of bryozoan forms on its weathered surfaces. The strata are bent up into a sharp syncline whose axis runs north-east, the remnant now existing being less than a mile in length and 300 yards in breadth. The underlying beds are naturally existent over a somewhat wider area, and extend across the Mandamus towards the Hurunui, the direction of one of the reaches of this stream corresponding in alignment and direction to that of the axis of the syncline.

The limestone has evidently been squeezed up by folding movements and has occupied the structural basin in which it lies, but the form of the land surface on which the limestone was laid down was not basin-shaped. There are similar basins in the country to the north-west, with parallel orientation, which do not now contain limestone outliers, but their form is so characteristic that their origin is probably similar to that of the Dove. These parallel elements may explain the north-easterly direction of the Hurunui in this part of its course, for after it leaves Maori Gully it apparently follows the line of these basins, with breaks across from one to another.

It may be noted also that the hills in this part of the valley rarely exceed 3,000 ft., but immediately to the north-west mountains rise to between 5,000ft. and 6,000ft., the marked difference in height being perhaps due to the fact that the lower area was faulted down along a line of settlement parallel to those occurring a short distance away in the Hanmer area and still farther away in the Kaikouras.

The indications certainly point to this submontane area having been covered with a veneer of sediments during Tertiary times; that it was raised with some faulting, and certainly with folding, in late Tertiary or in Quaternary times, the folding producing anticlines and synclines of the beds of limestone with a general north-easterly trend; and that these limestones were removed from the basins with the exception of that of the Dove. The drainage which now occurs may be called, as Cotton has suggested (1917, p. 253), “anteconsequent,” in that it was perhaps consequent on the former land surface, but antecedent as far as the present surface is concerned. The determining factors of the original consequent drainage must in this case be highly speculative and almost impossible to determine.

(2.) Hurunui-Waiau Basin.

The salient features of the Hurunui-Waiau basin have been mentioned before by myself (1915, pp. 347–48). The formation of this mountainringed area is attributable primarily to faulting or folding movements, or a combination of both, for there is ample evidence that both are present. The Tertiaries on the north-west side of the basin lie on the basement beds of greywacke with a general dip to the south-east, but with occasional reversals where they abut against the older rocks. This is specially well seen near the road past Mount Mason into the Virginia country, where the limestones in close proximity to the greywackes experience a sharp fold

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backwards as if the beds had been dragged down along a fault-line. Farther north towards the Hurunui Gorge, opposite their junction with the Mandamus, they appear quite normal, but in the Pahau again their structure is obscure, though that may be attributed to the disturbance in the immediate neighbourhood of a volcanic vent. Farther north-east towards Culverden their arrangement is again normal. The floor of the basin is almost completely masked by the gravels of the Hurunui and Pahau Rivers, the only indication of what is underneath being given in the vicinity of Hurunui Mound. Here the Tertiaries rise like an island in the sea of gravels, and they are evidently folded acutely. In the cliffs on the bank of the river near the railway-bridge the structure is anticlinal, but at the Mound itself, about half a mile to the north-east, the beds are also folded, though not on the same line. There is evidence, therefore, of a more complex structure under the plains—that is, they approach a synclinorium.

The southern margin of the plain from the road-bridge eastward is determined by a fault-scarp, along the foot of which the river flows. The settlement of the block of country under the plains appears to be more marked on the south-east side (cf. the Waikari and Greta Valleys, also the fault system of the Kaikouras: Cotton, 1914), and the river has therefore occupied it as the lowest level possible on the plains. The outlet, however, is marked by high-level terraces indicating a former higher level of the river. It is almost certain, therefore, that the deformational movements which caused the basin had not terminated when the river had established its course through the gap at the south-east corner of the plains. Of such recent movements the surrounding districts furnish ample evidence (cf. the fault-scarps near Hanmer, at Glen Wye, and also the recent gorge of the Middle Waipara). The course of the river from the junction of the Mandamus has followed the line of steepest descent to the fault-line, and is therefore approximately at right angles thereto. This explains the necessity of the sudden sharp turn when the line of the fault is reached. Although the high-level terraces at the outlet may be attributed to recent movements in the basin itself, they may be correlated with the uplift which all this region has recently experienced, and therefore are the result of the river accommodating itself to a new and lower base-level. The river-course across the plains is marked by terraces of no great height. It here follows a direction consequent on a surface of its own making, for which the term auto-consequent could be used. Thus the courses of the Rakaia, Rangitata, and other large rivers of Canterbury across the plains are auto-consequent.

(3.) The Waikari-Kaiwara Basin.

After leaving the Culverden Plain the river flows through a gorge cut in greywacke for about six miles till it enters on the Waikari-Kaiwara basin. This extends down the river to the immediate vicinity of the Ethelton railway-station, when the river passes through another gorge cut in greywacke. The basin is therefore completely enclosed by pre-Tertiary rocks. Although the area has a basin-shaped form, its origin is somewhat different from the Waiau-Hurunui intermontane area, and owes its formation entirely to the faulting-down of a strip of Tertiary beds and the subsequent enlargement of the tributary valleys through the rapid erosion of relatively weak beds. These consist chiefly of sands with harder concretionary bands, sandy clays, and marls, with occasional irregular layers of shells, mostly in a fragmentary condition: they are, in fact, the equivalents of the Motunau or Greta beds. Mount Brown beds are existent

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as well, but I have found no appearance of limestone, which is so well developed in the Waikari district to the south-west. Limestone does occur in the upper part of the Scargill Valley, in the form of faulted strips, but I have not traced it farther towards the Hurunui. The beds have a general north-east strike, and a dip to the south-east of from 150 to 200 Where the beds cut across the Hurunui, which they do at an angle of about 450, they are disturbed from their proper dip and are pulled up along the line of a fault on the downthrow side till they are nearly vertical; but this disturbance does not extend far from the fault-line, and may be attributed entirely to the movements caused by it. The result is that the beds form a strip running along the north-west side of the Waikari-Kaiwara depression, with slope accordant to that of the underlying surface, and if they were removed a characteristic “stripped surface,” as described by Thomson,* would be disclosed. I do not know what special name has been applied to valleys of this form, except that I think the term “basin range valley” has been applied to somewhat similar valleys in the western United States; but the Waikari Valley is of a somewhat different type, and also the name just cited is an unfortunate conjunction of terms. The name “rift valley” does not apply, because such are determined by faulting running along two sides, whereas these under consideration are attributable to tilting which has accompanied faulting along one line only. I suggest the name tilted strip as being a suitable name in case none has been already applied.

The most remarkable feature of the course of the Hurunui is its continuance across this depression without any apparent effect on its course. Although the earth-movements accompanying the faulting must have been of fairly recent date, the river has maintained its original course. It is interesting to compare this case with that of the Clarence Valley, farther north, where a similar valley caused by faulting on a much larger scale has dominated the course of the river. In the case of the Hurunui the movement must have been slow, and some cause must have been present which enabled the river to reach a lower base-level almost as fast as the downward movement occurred in the beds in this portion of its course. This cause will be evident from a consideration of the features of the next compartment into which the river-valley has been divided.

(4.) The Greta-Cheviot Basin.

The greywacke gorge of the river continues for about three miles below the Ethelton Station, when the valley opens out and the river has a wide shingly bed with flanking terraces cut in the marls of the Motunau or Greta series. Soon after its emergence from the gorge it receives the small Greta Creek, which occupies a valley similar in form and origin to that of the Waikari and Kaiwara. The beds let down by the fault which determines this valley develop northward into those of the true Cheviot basin, which is some five miles across, and extends past the Cheviot township across the Waiau as far as the Conway River. The structure of this basin is dominantly synclinal. The beds exposed on the floor of the basin are clays, sandy clays, sands, & c., of Mio-Pliocene age, passing down conformably into calcareous greensands (— Weka Pass stone) and hard limestone (— Amuri limestone). The limestone is exposed in places along the western edge of the greywacke ridge which separates the basin from the sea, and through which the Jed has cut its gorge. On the seaward side of this grey-

[Footnote] * J. A. Thomson, Coal Prospects of the Waimate District, South Canterbury, N.Z. Geol. Survey, 8th Ann. Rep., p. 160, 1914.

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wacke barrier the limestone also occurs, with reversed dip, and under the limestones are exposed sands and greensands with saurian bones, and thin beds of impure coal. On following the beds across the strike a synclinal arrangement is found, and the limestone forming the south-eastern limb appears as a reef at Port Robinson, striking out to sea just as the limestone reefs do at Amuri Bluff. This syncline is well seen in the cliffs at Gore Bay, and it no doubt extends south-west as far as the Hurunui, and appears where the rocks dip up-stream just above the lowest bridge across the river. The upturned beds of the south-easterly wing of this syncline rest at Port Robinson on greywackes, and at the Hurunui Bridge on the same rocks. In the last-mentioned locality there is evidence that the Tertiaries are bent over this core of greywacke in mild anticlinal arrangement. The river has cut a gorge through the greywacke, which has been used as a solid basis for the abutments of the bridge.

Up-stream from this, the traces of the anticlines and synclines which occur between Port Robinson and Cheviot can be seen occasionally where the Motunau beds are exposed in the river-terraces, but no limestone is visible; the general arrangement is, however, synclinal.

An important point as regards the history of the river is the comparatively recent elevation of the coast-line. This has amounted to as much as 600 ft., judging from the shore-platforms extending to that height at Port Robinson, between the mouths of the Hurunui and the Blyth Rivers (three miles to the south), and just south of the Blyth River on the summit of the Napenape Cliffs. This elevation has been noted previously by Haast, Hutton, and McKay. In the last-named locality there are sea planed limestone surfaces 600ft. above sea-level covered in places with marine gravels. In the country just south of the Hurunui this plain of marine denudation extends back from the present coast-line for some five miles to the base of the greywacke hills, and exhibits a peculiarity in that the wave-cut surface is higher near the coast than farther inland. This suggests that a slight warping has taken place since the plain was cut; but the peculiarity may perhaps be explained by the more ready erosion of the softer beds farther inland than the harder limestone exposed near the coast where it forms the floor of the high platforms. The first explanation is, however, the more reasonable, and if it is correct the axis of warping would approximate to that of the line of the greywacke bar near the river mouth. Apart from the effect on the river in this vicinity, probably apparent in the gorge of the river incised in a somewhat wide flood-plain, an elevation of the land totalling some 600 ft. would exert considerable influence on a river which had reached approximate base-level, as it is reasonably certain that the Hurunui had, before the coastal elevation took place. The power of vertical corrasion would be greatly increased over a considerable part of the course of the river. At the present time a considerable portion of the Culverden Plains are under 600 ft. above the sea, and unless some compensations in level have taken place inside the coastal belt the level of the riverbed should have been greatly affected as far as the junction with the Mandamus at least, where the solid bars of rock would delay adjustment for a long period after it had taken place in the relatively weaker beds farther down-stream. There is, however, evidence of a lowering of the inland portion of the river-basin relative to the coastal portion as a result of the faulting which took place on the Greta line, on the Waikari-Kaiwara line, and again in the deformational movements of the Hurunui-Waiau basin. The effect of this would be to make this portion of the stream an aggrading one if the lowering were in excess of the coastal elevation. This has certainly been the case, for the aggregate throw of the faults must total

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considerably over this. The effect of this has no doubt been to make the river an aggrading stream in that part of its course which lies in the Culverden Plain, and to neutralize the effect of the elevation perhaps as far down as Ethelton, but to rejuvenate the part between the Greta and the sea. Even this part is near a temporary base-level, judging by the great amount of shingle in its bed and the very low terraces of some parts of its course. This rejuvenation enabled the river to maintain its course in its lower portion across the grain of the country, to cut deep gorges through greywacke rocks, and to do this in spite of movements which would tend to turn it from its original course. As the present valley of the river is situated, there are several easier routes than that which it actually follows, such as that past Hawarden down the Waikari Valley, or past Hawarden into the valley of the Waipara and thus into the sea near Amberley. But it appears that under certain conditions, when the course of a river is once definitely established it will maintain that position in spite of influences which should divert it from its original path.

Development Of The Course Of The Hurunui River.

The géological features of this region which have primarily determined the course of the river are briefly stated as follows: On a greywacke surface, incompletely base-levelled, a series of beds was deposited chiefly in middle and late Tertiary times. These consist of sands sometimes with coal, greensands, limestones, marls, sandy shell-beds, and sandy marls passing up into conglomerates, the higher members being of Pliocene age. The general character of the strata indicates deposition on a sinking sea bottom in the early part of the period, followed by deposition on a rising bottom at the end, the whole sequence being laid down without a physical break. It is probable that there was some differential elevation towards the close of the time, so that some of the earlier beds were eroded in places while continuous deposition was going on elsewhere. The sea in which deposition took place gradually extended over a wider area with the sinking of the land, since the higher members overlap the lower and cover a more extensive area. Thus it is that limestone is very thin or entirely absent in certain localities—for example, the Greta and Waikari Valleys—the land occupied by those localities being the last to be invaded by the sea during submergence, and having an entirely different form from that which it now has. No doubt a slightly elevated area occupied the site of those valleys in early Tertiary times.

The covering beds extended far to the eastward, but have been cut back by marine erosion, which is at present making marked inroads on the sea-cliffs composed of loose sands and marls; while to the westward the Tertiaries extended beyond the Mandamus River, probably to the vicinity of Maori Gully, but fragments of the greywackes rose like islands in the cover of more recent beds, though not in the position of the high lands existing at present.

On this surface of covering beds as it emerged from the sea a consequent drainage was established, consisting of subparallel streams running seaward in an easterly direction. Although it cannot be stated with certainty, it is probable that the first elevation of the land took place with comparatively little deformation, and the river-courses were well established before the dislocations became pronounced. After the rivers had been completely established, folding and faulting took place on lines cutting the direction of the main streams at an angle of approximately 450, and these lines have determined the courses of the principal tributaries, most of which enter the main valley along fold and fault lines. The recency of the movements is

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emphasized by the marked dependence of the landscape forms on the features resulting immediately from these movements. In some cases time has not been sufficient for the weak covering beds to be removed from the higher elevations, though in general these are more perfectly preserved in the folded and faulted intermonts. The movements producing these must have been slow, although they have been comparatively recent, since the main stream has preserved its original direction with but slight modifications, in spite of the opportunities presented for departing from it as a result of these movements, while farther north in the Kaikoura region the movements were on such a scale that the stream-systems are almost entirely dependent on them for their direction. The Hurunui region thus illustrates the condition that a powerful stream may at times maintain its original direction in spite of strong forces tending to deflect it. Dr. Cotton has drawn my attention to a paragraph in a paper by Professor W. M. Davis, entitled “An Excursion in Bosnia, Hercegovina, and Dalmatia,” * which seems appropriate in this connection. It reads as follows:” It is evident that this hypothesis [warping] accounts simply enough for the occurrence of irregularly alternating basins and uplands; and that the basins thus produced might be connected by gorges eroded through the uplands by the master rivers; the gorges marking either the paths of antecedent streams that had maintained their course in spite of the warping, or paths selected by the drainage consequent on some early stage of warping and antecedent to the rest.” This idea of anteconsequent streams has been elaborated by Cotton (1917, p. 253), and it seems entirely applicable to the case of the Hurunui, except that faulting has ensued as a result of the strains set up in the warping movements.

Glacial Features of the Hurunui Valley.

(See map, fig. 2.)

Although there are no present-day glaciers in the valley of the Hurunui, the mountains not being sufficiently high in that part of the alpine region to intercept sufficient snow to feed them, the upper part of its basin was subjected to the severe glaciation which affected a large part of the South Island of New Zealand in Pleistocene times and perhaps later. Haast has indicated (1879, plate 11) that the Hurunui Glacier at its greatest extension came down below the junction of the Waitohi River with the main stream—that is, well on to the Culverden Plains; but on what evidence he bases this great extension is not clear, and in my opinion there is no reason to demand it. The absence of morainic and other glacial deposits, as well as the form of the river-valleys in the middle course of the Hurunui, render his supposition very improbable. Especially is the latter evidence strong in the case of Maori Gully, the striking gorge which the river has cut in the edge of the high-mountain country before it runs through the foothills of the Alps. This is so deep and narrow that it is almost impossible that ice could have come through it and left it in its present condition. It seems to me extremely probable that the ice did not extend below the junction of the two main branches of the river, if, indeed, it came so far, since there is no proof of its former presence even at this point except the somewhat indefinite evidence based on the form of the river-valley, which may be attributable to ice action or may be the result of ordinary stream erosion. In the absence of other proof this solitary line of evidence must be viewed with considerable reserve.

[Footnote] * Bull. Geog. Soc. Philadelphia, vol. 3, No. 2, pp. 21–50, 1901.

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Above the junction of the two branches the evidence is undoubted, especially from the vicinity of the Lakes Station and Lake Sumner towards the head of the river. Old moraines, smoothed and rounded surfaces, and the form of the cross-section of the valleys furnish indubitable evidence of the former presence of ice. In the upper part of the course of the North Branch the even alignment of the valley-walls, their steep lower slopes and gentler upper ones, the truncated and semitruncated spurs, and the roches moutonnées on the valley-floor are as characteristic of the results of glaciation as anything in the valleys of the Southern Alps farther south. On the north side of the river the mountain-tops have a very flat plateau-like form, and this feature continues as far as the valley of the Waiau, if not farther, so that the streams run in deep trenches incised in the tableland. To the south of the river the mountain-tops are more like those characteristic of middle and southern Canterbury, with rugged summits and wide expanses of moving debris dislodged from solid rocks by the action of frost. To the east of the plateau region the mountains take on this form even to the north of the river.

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Fig 2.—Upper Hurunui Valley.

Specially interesting features of the river-basin have resulted from the action of these ancient glaciers on a mature valley-system which had become established in pre-glacial times. These features are so strongly reminiscent of those of the valleys farther south, especially of the Waimakariri, that they must be attributable to a common cause. The only difference in the two cases is that the features of the Hurunui are not so strongly marked, which is no doubt due to the more moderate intensity of the glaciation in the northern river. Thus there are distinct traces of the original directions of the streams, which are wanting farther south, but which may give some clue to the origin of the characteristic features of the valleys.

Parallel Valley System of Upper Part of Basin.

The most striking landscape form of the upper basin of the Hurunui is the series of subparallel valleys flanking the North Branch on its southern side. These are quite analogous to those of the Waimakariri, also on its southern side, and to those in the vicinity of Lake Coleridge in the valley

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of the Rakaia. The arrangement is as follows, taking the valleys in their turn, commencing from the north:—

(1.)

The main valley of the North Branch leading into Lake Sumner. This has a general east-and-west trend, with wall-like sides in good alignment, but broken by tributary valleys, especially on its northern side. Lake Sumner occupies a continuation of this valley, but about half-way along the lake the trend assumes a north-west and south-east direction more in agreement with that of the others. This corresponds in direction and salient features with the main valley of the Waimakariri, but the landscape characters are on a smaller scale.

(2.)

The set of subparallel valleys leading from the vicinity of the head of Lake Sumner, near Lake Katrine, and running south-east. At the head of the system there is only one main valley, but it breaks up within a short distance into distributaries consisting of—(i) A valley immediately to the south of Lake Sumner and divided therefrom by a ridge of which the peaks known as The Brothers (4,563 ft. and 4,507 ft.) are the highest points; (ii) a valley in which lies Lake Sheppard, divided from (i) by a discontinuous ridge ending in The Sisters (3,281 ft.); (iii) a valley in which lies Lake Taylor, divided from the former by Conical Hill (2,783 ft.) and from the valley of the South Branch by the Oronoko Range. These valleys are quite analogous to those in the Waimakariri basin, which may be called (i) the Lake Black-water Valley, (ii) the Lake Sarah – Sloven's Creek Valley, and (iii) the Lake Grassmere – Lake Pearson – Winding Creek Valley. They also resemble the still more remarkable and perfect system to the east of the Rakaia basin in the vicinity of Lake Coleridge.

The ridges which divide these valleys are analogous in their physical characters. They are very steep-sided, with somewhat narrowed crosssection, so that when viewed end-on they appear conical; hence the frequent occurrence of such names as “Sugarloaf” and “Conical Hill” in North Canterbury. But when viewed from the side they form long ridges cut into well-defined saddles (cf. Mitre Peak). When this saddle is low and little elevated above the floor of the valley in the vicinity the ridges become isolated hills, which are often in pairs or linear series, and give rise to such names as “The Brothers” or “The Sisters.”

The valleys indicated above junction with the main valley of the North Branch after it leaves Lake Sumner and takes the first decided bend of the river to the south-east. It soon afterwards receives the South Branch. In its upper part this valley has an east-west direction, but it soon takes on the characteristic north-west and south-east orientation, and finally turns and joins the other branch nearly at right angles. The dividing wall between it and the Lake Taylor Valley to the north, called the Oronoko Range, has been partially broken down in several places. The most important of these lies just opposite the head of Lake Sumner, where a low pass leads from the northern to the southern valley of the Hurunui. On the southern side of the pass is Lake Mason, tucked away in a tributary valley of the South Branch. The country in this neighbourhood has been highly glaciated, roches moutonnées and smoothed surfaces forming characteristic features of the landscape. Opposite the Lakes Station there is another saddle—some-what high, it is true—and the ridge has also been lowered in a line with the Lake Taylor Valley leading directly to the North Branch south of Dog Hill, indicating an overflow in that direction.

The partial dismemberment of this ridge affords a clue to the conditions which obtained before dissection and isolation overtook the ridges to the north-east. By noting its features it is possible to restore with reasonable

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certainty the general direction of the streams that flowed through this tract of country anterior to the glaciation. In addition to the two main branches of the river a large stream rising near the head of Lake Sumner followed the course of the Lake Taylor Valley, parallel with the South Branch; this entered the North Branch about half-way between Lake Sumner and the junction of the two main branches. A small tributary entered this valley on the north side, rising near the head of Lake Taylor and following the course of Lake Sheppard. Another small stream rose near Lake Katrine and joined the North Branch below the outlet of Lake Sumner. In pre-glacial times the ridges dividing these valleys would be more or less entire, though they might have saddles at their heads. It is impossible to reconstruct such features exactly, but the description just given affords a fairly accurate view of the stream conditions which obtained in this tract of country before it was modified by glaciation.

Whatever was the prime cause which promoted glacier extension, it is reasonable to assume that it was gradual in its incidence. Snow would slowly accumulate, glaciers would be formed at higher altitudes and slowly extend down the valleys. Thus the heads of the small valleys would probably be filled with corrie glaciers, while the glaciers of the first order would be extending down the main valleys. These would help to lower the divides in the way suggested by Matthes.* As the ice-flow increased in volume the main streams would be filled, and in time overflows would take place over the lowest part of the divides, which would be lowered at the same time by active ice abrasion. It is significant that the greatest amount of lowering has taken place near the head of Lake Sumner. This would be due to the marked overflow of ice from the main Hurunui Valley, no doubt due to the narrowing of the cross-section of the valley at Lake Sumner, which caused the ice to overcrowd into the headwaters of the neighbouring streams, as it has done in several of the valleys of the Canterbury rivers. The full force of this would be felt at the head of the Lake Taylor Valley, and thus its divide has been completely reduced. The headwaters of the intermediate tributary valleys were also invaded and the saddles at their heads reduced. Thus a clear passage for the ice was opened down these valleys past the site of the Lakes Station in the direction of the south-easterly reach of the North Branch below Lake Sumner, while the main stream of ice followed down the valley now occupied by this lake.

In addition to the overflow toward Lake Taylor a powerful stream passed over into the tributary which runs into the South Branch from the north. The saddle at the head of this stream was thus reduced, but not so much as its neighbour, which was more in the line where the ice-stream would impinge on the valley-wall. If, however, glacier action had continued this saddle would have been reduced and the mountain ridge to the north of the South Branch would have been completely isolated. It is possible that ice also overflowed into the valley of this stream near the Lakes Station, and as at the height of the glaciation the country in its vicinity would have the form of an intermontane basin, and would be an efficient gathering-ground, overflows from it took place along several lines from the front of the ice-sheet in the direction of the valley of the North Branch. These would produce the breaks in the valley-wall between the South Branch and the country to the north which occur immediately up-stream from the junction of the two branches.

[Footnote] * F. E. Matthes, Glaciation of the Big Horn Mountains, U.S. Geol. Surv. 21st Ann. Rep., 1899–1900.

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The dismemberment of the ridges would no doubt be promoted by the sapping-back of the valley-walls and their complete reduction in places where the ice-stream impinged more powerfully. If we compare the results of the glaciation in other valleys we see that in their cases the dismemberment has been more complete, the dissection of the dividing ridges carried to a further stage, and the straightening of their sides more thoroughly carried out, because they experienced more complete glaciation. If we were furnished in these cases with more clear indication of the intermediate condition of the direction of drainage it would be possible to reconstruct the original stream-system.

There is one point, however, which has not been considered fully—viz., the agreement in the direction of the tributary valleys with those of the Waimakariri and Rakaia. Is this agreement in orientation the result of accident, or is it based on some structural condition which has influenced the country in the basin of the Hurunui as well as the country farther south?

I have shown (1916, pp. 142–43) that there exists in the mountain region of Canterbury a well-marked series of fractures or lines of folding which lie in a north-west and south-east direction. Cotton (1917, p. 273) draws special attention to the importance of the north-west system of earth-fractures in Otago as compared with the other parts of this Island, but they certainly occur in Canterbury in conjunction with the Kaikoura system, and it is possible that in the upper Hurunui, as in the Waimakariri, they are co-existent. Since writing the article referred to above I have noted additional lines with the north-west orientation, especially in the upper valley of the Waipara and in South Canterbury in the country between Fairlie and Cave. In both these cases there are undoubted, well-marked lines of fault. It is possible, therefore, that the general direction of the valleys at the head of the Hurunui were determined initially by lines of structural weakness. It is remarkable also that some of the valleys on the northern side of the river have a characteristic east-north-east orientation, and these are parallel to other valleys farther north, such as the Hope, in the basm of the Waiau. On the line of one of these upper valleys is the hot spring which forms a notewerthy physical feature of the Upper Hurunui, and I am informed that other springs occur in the valley which stretches north-east from this locality. This certainly points to the presence of an earth-fracture with east-north-east orientation.

Another feature of this district should be noted—viz., the north-and-south trend of the upper valleys of the Waiau and Clarence, a direction which is parallel to the twin valleys of the Mandamus, and to that of the Glenrae, lying to the west of these. The arrangement may be only a coincidence, but it is certainly a striking one.

Bibliography.

Cotton, C. A., 1914. The Physiography of the Middle Clarence Valley, New Zealand, Geog. Journ., vol. 42, pp. 225–46.

—— 1917. Block Mountains in New Zealand, Am. Journ. Sct., vol. 44, pp. 249–93.

Haast, J. von, 1971. Rep. Geol. Explor. dur. 1870–71, pp. 30, 48, sections.

—— 1879, Geology of Canterbury and Westland, pp. 69–78, 216–17.

Hutton, F. W., 1877. Rep. Geol. Explor. dur. 1873–74, pp. 34–35, 55–56.

—— 1889. The Eruptive Rocks of New Zealand, Trans. Roy. Soc. N.S.W., vol. 23, pp. 125, 156.

Speight, R., 1915. The Intermontane Basins of Canterbury, Trans. N.Z. Inst., vol. 47, pp. 347–48.

—— 1916. The Orientation of the River-valleys of Canterbury, Trans. N.Z. Inst., vol. 48, pp. 137–44.

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Art, VII.—The Volcanic Rocks of Oamaru, with Special Reference to their Position in the Stratigraphical Series.

[Read before the Wellington Philosophical Society, 16th July, 1916; received by Editors, 31st December, 1917; issued separately, 24th May, 1918.]

Contents.

I.

Introduction.

II.

Succession of the Rocks of the Oamaru Series.

III.

Previous Opinions in regard to the Horizon of the Volcanic Rocks.

IV.

Effects of these Opinions on the Classification of the Oamaru Series.

V.

Descriptions of the Sections.

(1.)

Oamaru Lighthouse.

(2.)

Oamaru Rifle Butts.

(3.)

Hutchinson Quarry and Neighbourhood.

VI.

The Pillow-lavas.

VII.

Chemical and Petrographical Notes.

VIII.

Conclusion.

I. Introduction.

Interpretations of the geology of the Oamaru coastal district where the typical Oamaru series is developed have varied greatly in the past, and, although there is now pretty general agreement as to the broad features of the rock-sequence, it is essential that more detailed stratigraphical work should be attempted if the best results are to be obtained from the determinations of the Tertiary fossil Mollusca and Brachiopoda, which are being carried out by Mr. H. Suter and Dr. J. Allan Thomson. Many of these fossils have been collected from the Oamaru district, the exact locality and rock from which they have been gathered are known, and, if the stratigraphical sequence can be determined in greater detail than has been done in the past, correlation of Tertiary rocks in other parts of the Dominion with those developed in the typical locality will possess a sounder basis than it does at present.

Misinterpretations of the rock-sequence at Oamaru have undoubtedly been caused by faulty identification of the horizons of the volcanic rocks, and it will assist stratigraphical work if these can be determined more accurately.

The position of the lowest volcanic rocks, the Waiarekan, is not in question; it is generally agreed that they lie immediately below the Ototara limestone, and my work in the North Otago district has convinced me that they are invariably associated with deposits of diatomaceous earth in the Oamaru and Papakaio areas. Difference of opinion has, however, been sharply marked when dealing with the volcanic rocks near the Oamaru coast. These have been correlated with the tuffs in the Waiareka area; important unconformities have been introduced into the sequence, on the ground that the volcanic rocks are clear evidence of the existence of a former land surface. An attempt will be made in the present paper to define more clearly the place of the volcanic episodes in the late geological history of the Oamaru district. In 1916 I gave a detailed sequence of the rocks east of the Waiareka Valley, and some of the evidence on which the succession was based was presented in that paper. It is now proposed to bring additional evidence by describing several sections in the neighbourhood

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of the town of Oamaru. The pillow-lavas that occur in some localities will be described, and a preliminary reference will be made to the microscopic characters of some of the rocks, a detailed description of which must be reserved for a future paper. I am much indebted to Dr. Thomson and Mr. H. Suter for naming many of the fossils. Their determinations are indicated by an asterisk placed in front of the name of the fossil. The other determinations have been made by myself by comparison with forms determined by these palaeontologists.

II. The Succession Of The Rocks Of The Oamaru Series.

It will be advisable at the outset to state briefly the detailed succession of the Oamaru series as developed in the typical locality. The classification of the upper rocks is based mainly on evidence to be brought forward in this paper.

To the west of Oamaru, in the basin of the Kakanui River, the lowest Tertiary rocks are the grits, clays, and sandstones, sometimes associated with lignite deposits, the whole forming the Ngaparan stage. These are followed by a considerable thickness of greensands, and these in turn are succeeded by a great thickness of breccias and tuffs, occurring in the Waiareka Valley. Towards the top these become fine-grained and tachylytic, and are interbedded with deposits of diatomaceous earth, which, in addition to the vegetable micro-organisms, contains an equal abundance of spongeremains and Radiolaria. Dykes and sills have intruded the tuffs and diatomaceous earth, and the siliceous rock has in many places been completely metamorphosed into a flinty substance. These constitute the Waiarekan stage. The Ototara limestone is the next succeeding rock. In its lower portions it is interstratified with thin beds of marl, and occasional thin layers of rolled volcanic pebbles. In its middle portion it is in some localities intercalated with tufaceous bands, but these are probably detrital only. In other localities the deposition of the limestone continued uninterruptedly; and it is free from volcanic material. Towards the end of the limestone period volcanic activity was renewed in localities near the present coastline with the eruption of the breccia at Kakanui and the volcanic rocks in the neighbourhood of Oamaru, the upper pillow-lava of the latter locality being younger than the breccia. After volcanic action had ceased limestone continued to be deposited, but in many places it contains large well-rounded masses of volcanic rocks, and minerals similar to those occurring in the breccia below. It is more than probable that the Kakanui breccia formed small islands or submarine banks, for it is followed by limestone bands and tuffs, the former containing rolled fragments of the breccia. In Oamaru Creek these interstratified tuffs and calcareous bands are invaded by a thick mass of dolerite which has overflowed to the north and formed the upper pillow-lava near Grant's Creek. This in its turn is followed by the limestone containing the large volcanic boulders. The latter disappear towards the top of the limestone, which closes the Ototaran stage. The greensands of the Hutchinsonian stage followed the limestone, and the sequence closed with the mudstones of the Awamoan stage.

III. Previous Opinion in regard to the Horizon of the Volcanic Rocks.

Hector (1865) considered that the volcanic rocks near Hutchinson Quarry, in the town of Oamaru, were submarine, but he based his conclusion on the

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erroneous assumption that the hard limestone bands in that locality had been metamorphosed during deposition by a lava-flow.

Hutton (1875, p. 54) said, “No eruptive rocks are found associated with the older or Ototara group of strata …. but at Oamaru Heads we have clear evidence that during the deposition of the Upper or Trelissic group of beds volcanic action was going on.”

In 1876 McKay placed the Waiareka tuffs below the Ototara stone, and asserted that a younger series of volcanic rocks occurred at Oamaru.

In 1886 Hutton verified McKay's observations as to the position of the Waiareka tuffs, but repudiated his own former statement that volcanic rocks were associated with the upper beds of the series. He recognized but one horizon of volcanic rocks, the Waiarekan, and considered that the volcanic matter in the upper part of the limestone was detrital only.

In 1905 Park asserted that volcanic activity commenced at the end of the Waihao greensand period and culminated during the deposition of the Hutchinson Quarry beds.

Summarily, according to McKay there were two distinct periods of eruption, the pre-Ototaran and the pre-Hutchinsonian; according to Hutton but one, the pre-Ototaran; while according to Park activity continued during the Waiarekan, Ototaran, and Hutchinsonian periods.

IV. Effects of these Opinions on the Classification of the Oamaru Series.

The fact that the volcanic rocks are always followed by limestone has undoubtedly caused confusion in classification, and in the absence of distinctive fossils in the limestone the igneous rocks near the coast have been assumed to be Waiarekan. McKay, although recognizing the Tertiary volcanics at Oamaru as distinct from his Cretaceo-Tertiary Waiarekan tuffs, erroneously supposed the breccias at Kakanui to be Waiarekan (1877, p. 56), whereas they are middle Ototaran. Hutton in ascribing the volcanic rocks at Oamaru to the Waiarekan was necessarily compelled to introduce an unconformity above them to account for the non-existence of the Ototara stone. Park's contention that volcanic activity culminated during the Hutchinson Quarry period may be true or not true; it depends entirely on the connotation of the term “Hutchinson Quarry beds.” McKay seems to have been the first geologist to use the term in classification (1882, p. 58). Later in the same report (p. 76) he seems to restrict the term to the greensands alone, correlating the calcareous beds with the Otekaika limestone, and the volcanic rocks below with the Kekenodon beds. In other words, in the typical locality he excludes the limestone bands. This is in substantial agreement with Thomson's use of the term “Hutchinsonian” (1916, p. 34).

Hutton was probably correct in considering much of the volcanic matter detrital only, as will be demonstrated in the sequel. Further, McKay considered the volcanic rocks of Oamaru Creek as evidence of a land surface, and he supposed the overlying rocks to be markedly unconformable to them (1877, p. 58). My own opinion, based on the evidence furnished below and on further observations in other parts of the Oamaru district, is that deposition was continuous from the base of the Ototaran to the top of the Awamoan, but interrupted locally by submarine eruptions resulting in the formation of volcanic banks or islands, which, however, suffered rapid denudation, and this minor phase is recorded in the slight unconformities now to be seen in the tufaceous beds.

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V. Descriptions of the Sections.

(1.) Oamaru Lighthouse.

In the sea-cliff below the lighthouse near the Oamaru Breakwater a good section is exposed (see fig. 1).

The tufaceous beds (a) are interstratified with limestone bands, which often contain large subangular pieces of vesicular basalt. The bands themselves vary up to 1 ft. in thickness, the lowest being 170 ft. below the base of the lower pillow-lava. There is a marked discordance in the dip of the tufaceous rocks below (a). These are not shown in the figure. They dip 40° N. by E., while the dip of (a) is only 20° N. by E. It is probably at this point that McKay introduces his unconformity between his Cretaceo-Tertiary and Upper Eocene beds (1877, p. 58). From the calcareous bands in the tuffs I collected the following forms: *Emarginula wannonensis Harris, Siphonalia sp., Dentalium solidum Hutt., *Pecten hutchinsoni Hutt., Siphonium planatum Suter, Liothyrella oamarutica (Boehm), L. boehmi Thomson, Terebratulina suessi (Hutt.), Aetheia gualteri (Morris), and Hemithyris sp.

The overlying pillow-lava is at a minimum estimate 100 ft. thick. The interspaces are filled with fossiliferous limestone, much hardened in places by a secondary deposit of calcite, and the fossils are difficult to extract A detailed description of this peculiar rock and others similar to it will be given later. The following fossils were obtained from the interstitial limestone: *Trochus sp., *Turritella sp., *Polinices huttoni von Ihering, *Lima bullata Born, *Lima lima (L.), Ostrea sp., and Hemithyris sp.

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Fig. 1.—Section near lighthouse, Oamaru. (a) Tuffs with limestone bands; (b) lower pillow-lava; (c) fine tuffs (current-bedded); (d) tuffbed (very calcareous); (e) limestone band with rounded and subangular pieces of volcanic rock: (f) blue tufaceous clay; (g) limestone; (h) tufaceous limestone; (j) raised beach; (k) broken pillow-lava.

The tuff-beds (c) are very fine and current-bedded, but unfossiliferous. The overlying tuffs (d) are very calcareous and coarser in texture. I collected the following forms: Epitonium lyratum (Zitt.), Lima jeffreysiana Tate, Ostrea sp., Venericardia purpurata (Desh.), and Diplodonta zelandica Gray.

The limestone band (e) is crowded with subangular pieces of volcanic rocks, while small pieces of augite were also identified. Bed (g) is a much purer limestone than bed (h), which is very tufaceous.

In the limestone (g) the following forms occurred: Epitonium lyratum (Zitt.), *Pecten hutchinsoni Hutt., *P. delicatulus Hutt., Terebratulina suessi (Hutt.), *Liothyrella boehmi Thomson (?), and *L. oamarutica Boehm.

The overlying tufaceous limestone (h) is also fossiliferous, and the following species were identified: *Limopsis aurita Brocchi, Pecten delicatulus Hutt., *Lima jeffreysiana Tate, Ostrea sp., *Venericardia purpurata (Desh.), V. zelandica (Desh.), Protocardia pulchella (Gray), and Terebratulina suessi (Hutt.).

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This bed passes insensibly into a completely tufaceous bed with occasional pillows scattered through it. The tufaceous matter, however, rapidly diminishes, and the rock becomes a pillow-lava, which will be discussed in the sequel.

(2.) Oamaru Rifle Butts.

Near the Oamaru Rifle Butts, on the south-west side of Oamaru Cape, a clear section is exposed on the beach. It is interesting, as the pillow-lavas are absent and a bed of limestone nearly 50 ft. thick is followed almost immediately by the Hutchinsonian greensands. A fault occurs immediately north of this section, and just beyond the fault there is a marked strati-graphical break in the tuff-beds, exactly similar to the unconformity described in the tuffs near the breakwater.

The section extends from a point immediately north of the target sheds to the fault which cuts the tuffs just past the first headland.

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Fig. 2.—Section northwards from Rifle Butts, distance about 160 yards. (a) and (a1) tuffs; (b) calcareous fossiliferous tuffs, 1 ft.; (c) limestone agglomerate, 2 ½ ft.; (d) (7 ft.) and (d1) (40 ft.) limestone; (e) fine blue tuffs, 8 ft.; (f) greenish calcareous tuffs, 11 ft.; (g) indurated nodular limestone, 4 ft. 4 in.; (h) brachiopod greensand; (i) shell-bed, 2 ft.; (j) blue clav 100 ft.; (k) raised beach.

The tuffs (a) and (a1) are calcareous throughout. From the band (b) I collected the following forms: Turbo sp., Turritella sp., Siphonalia conoidea Zitt., Venericardia purpurata (Desh.), Diplodonta zelandica Gray, Chione mesodesma Reeve (?), Dosinia caerulea Reeve, Mesodesma subtriangulatum (Gray), Siphonium planatum Suter, and Liothyrella oamarutica (Boehm).

Band (c) is a limestone crowded with subangular pieces of volcanic rock, with occasionally inclusions of a coarsely holocrystalline basic igneous rock. Masses of tuff, broken minerals, and pieces of rounded vesicular basalt occur, one of those being 1 ft. in diameter. The bed (e) is a fine brownish tuff weathering blue, and containing several limestone bands. I obtained the following fossils from one of these bands: *Pyrula sp., *Lima lima (L.), *Pecten sp., and Penacrinus sp.

Mr. Henry Suter writes in regard to the genus Pyrula, “It is an unexpected addition to our fauna, and indicates a much warmer sea, the genus living now only in tropical latitudes. It is not found Recent in Australasia, but a species was described in 1888 by Pritchard from the Eocene of Table Cape, Tasmania.”

The thicker bed of limestone (d) resembles the building-stone of the Oamaru district; it is poor in Mollusca and Brachiopoda, but I collected the following: Siphonium planatum Suter, *Pecten hutchinsoni Hutt., Aetheia gualteri (Morris), and Hemithyris sp.

Overlying the limestone is a fine light-greenish calcareous tufaceous mud, which is very fossiliferous. The species identified were: *Siphonalia conoidea (Zitt.), *Limopsis zitteli von Ihering, *Pecten delicatulus Hutt. *Lima angulata Sow., *L. bullata Born, *L. colorata Hutt., *Venericardia purpurata (Desh.), and *Mesodesma australe (Gmel.).

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The nodular limestone is of a similar character to the concretionary bands described by the present writer at Kakanui (1916, p. 23), but in the present occurrence there is very little glauconitic sandy material present, and the band is extremely hard throughout, the nodules being set in a calcareous matrix. The nodules vary in size up to the size of a cricket-ball; they show a concentric structure, with occasionally a central nucleus, while sometimes the centre is hollow.

The brachiopod band is a calcareous glauconitic sand, crowded with the typical Hutchinsonian fossil Pachymagas parki (Hutt.). Other species that occur are Pecten delicatulus Hutt. and Pecten (Pseudamusium) huttoni Park.

The shell-bed (i) is 2 ft. thick, and consists of a mass of shells embedded in fine grey sands. The fossils are much broken and very friable, and it was difficult to obtain specimens. The bed, however, is similar to the shell-beds at Target Gully and Ardgowan described by Marshall and myself (1913). One fossil obtained here was Aetheia gualteri (Morris), which has not hitherto been obtained above the characteristic Pachymagas parki greensands. Overlying the shell-bed is a blue mudstone with well-preserved fossils which clearly indicate that the bed is Awamoan. A list of fossils from this rock has been given by Marshall (1915, p. 384).

The two sections described above are exposed on the extreme north and extreme south respectively of a main anticlinal fold, the arch of which has been thrown into minor undulations and faulted in several places. Between the two exposures tuffs are exposed everywhere along the foreshore, but they have not yet proved fossiliferous. Although, as mentioned above, there are stratigraphical breaks in these tuffs and breccias, they are apparently of minor significance, as the rocks above and below are lithologically similar. Former observers have considered this underlying mass of volcanic rocks to be Waiarekan, but there is not the slightest positive evidence to support this contention. If they are Waiarekan, the breaks in the sequence mentioned above assume a much greater importance, for they will represent the time during which the greater part of the Ototara stone was being deposited.

(3.) Hutchinson Quarry and Neighbourhoods.

Near the abandoned quarry at Eden Street the typical Hutchinson Quarry beds occur. Although the exposures in this locality are small and disconnected, the succession is clear, and will be best represented by a diagrammatic vertical section.

The lowest beds are fine calcareous tufaceous rocks (a) weathering greenish-brown, containing in places large fragments of decomposed vesicular basalt, and ramified throughout by calcareous veins. The bed is 20 ft. thick in the section, but the base is not visible. This passes gradually into the overlying bed (b), which is 6 ft. in thickness. It is a confused mass of glauconitic sands, hardened limestone, and tufaceous matter. In places, however, the limestone shows lime in bands from 1 in. to 1 ft. in thickness. Fragments of fossils are visible but none are recognizable. Overlying is a mass

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Fig. 3—Section at Hutchinson Quarry. (a) Tufaceous rock, 20 ft.; (b) stone bands with tufaceous rock, 6 ft.; (c) limestone conglomerate, 11 ft.; (d) greensand, 15+ft.

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of limestone (c) thickly crowded with decomposed rolled volcanic rocks up to 1 ft. in diameter, while the limestone itself contains small fragments of augite and olivine. The junction of this bed with the underlying tufaceous bed is unconformable in the section, but is probably due to contemporaneous erosion. Towards the top the limestone is free from the conspicuous volcanic boulders, and becomes very hard. This limestone has been proved phosphatic. It is overlain by glauconitic greensand—the typical Hutchinson Quarry greensand—crowded with brachiopods belonging chiefly to the two species *Pachymagas parki (Hutt.) and *Rhizothyris rhizoida (Hutt.).

As the gully is followed towards the Oamaru reservoir, outcrops are conspicuous on the hillside, but the sequence is similar to that just described. Past the farmhouse, however, the underlying massive volcanic rock crops out, and this proves to be the same rock that occurs at Chelmers Street quarry as a thick dyke which has overflowed to the north, and developed pillow structure in the bed of Oamaru Creek near Grant's Creek. At the latter locality it clearly underlies a limestone “conglomerate” and limestone capped by the greensands, exactly as at Hutchinson Quarry. The section at Grant's Stream is described in another paper in this volume (p. 121). The brecciated pillow-lava is undoubtedly the same as the upper pillow-lava that occurs above the fossiliferous beds near Oamaru Breakwater (see p. 109). Park, McKay, and Hutton, in discussing the section at Oamaru Breakwater, referred these fossiliferous beds to the Hutchinson Quarry horizon; but whatever interpretation is given to this term, these beds at the breakwater are certainly below the volcanic rock which, at Hutchinson Quarry and the locality near Grant's Creek, is overlain in ascending order by tufaceous beds, from 10 ft. to 20 ft. of limestone, and the typical Hutchinson Quarry greensand.

The well-rounded appearance of the volcanic boulders in the limestone in the neigh bourhood of Oamaru Creek, and the confused intermingling of limestone, greensand, and rolled igneous rocks above the brecciated pillow-lava furnish evidence of denudation of the underlying volcanic rocks, which had formed small islands in the Tertiary sea. Formation of islands by submarine eruption is not an uncommon occurrence even in quite recent times, and has been noted by competent observers, who have always recorded the rapidity of their disappearance. This is probably the explanation of the various stratigraphical breaks that have been already referred to.

Lister (1891, pp. 596–606), in a paper on the geology of the Tonga Islands, arranges the islands in three main divisions—(a) purely volcanic islands; (b) islands formed of volcanic materials laid out beneath the sea, since elevated, with or without a covering of reef-limestones; (c) islands formed entirely of reef-limestone. Some of the islands of class (b) exhibit suggestive resemblances to the upper Ototaran rocks. These resemblances may be summarized under the following heads:—

(1.)

They are built up of layers of tuff capped by calcareous rocks;

(2.)

The fragments of some of the breccias are cemented by a calcareous matrix;

(3.)

Rounded boulders of volcanic rocks occur in layers embedded in a calcareous matrix;

(4.)

Some of the tuffs are penetrated by volcanic dykes which do not penetrate the overlying limestone;

(5.)

Fragments of basic plutonic rock occur on one of the islands;

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(6.)

Some of the limestones are not true coral-reef limestones, but, according to Sir John Murray, are “chiefly made up of calcareous organisms, fragments of molluscs, echinoderms, Polyzoa, and calcareous algae, together with a large number of Foraminifera.”

The plutonic rock mentioned above is a gabbro. Garnet also occurs, as it does in the Oamaru rocks. The intrusive rocks, however, are augite and hypersthene andesites.

In view of Mr. Suter's remarks in regard to the genus Pyrula, mentioned above, it is interesting to find that this genus occurs as a fossil in the tufaceous rocks of the island of Mango, one of the Tonga Islands.

VI. The Pillow-lavas.

Park (1905, p. 513) was the first geologist to recognize the lower rock near the breakwater as a pillow-lava. Since then the present writer has discovered the same peculiar rock in other localities of the district—in the basin of Oamaru Creek, and in the Awamoa Creek near Deborah. At the breakwater, also, the upper so-called “tachylyte breccia” is undoubtedly a pillow-lava which in parts has become brecciated, probably through local explosive action when coming into contact with the sea-water.

The lower pillow-lava (see fig. 1) consists mainly of spheroidal masses of lava with the interspaces filled with fossiliferous limestone. The junction with the tuffs below is quite even, and the surface of the tuffs shows no irregularity or indication of having been baked. The dip of these beds is N. 20° E. at an angle of 16°, and the tuff-beds overlying the lava have a similar dip. Each pillow has a tachylytic selvage about 1 in. in thickness, but the rock is holocrystalline at the centre. The pillows at the base of the flow are somewhat irregular in shape, but higher in the mass they become more spheroidal. One of the pillows near the base has a diameter of 30 ft. Higher in the section they are smaller, decreasing in diameter to about 2 ft., but towards the surface they again increase in size. Some of the pillows are much elongated; sometimes they show an indented periphery; occasionally the indentation has penetrated to the centre of the mass, and the upper half appears as if it had fallen over toward the lower half while still in a viscid state. Vesicles are by no means prominent in the rock. Occasionally large scattered ones occur, but on the tachylytic margin they are small and rounded. At the bottom of the flow the vesicles are small, and occur chiefly towards the exterior of the spheroid. Near the top of the lava the pillows are almost free from vesicles. By infiltration of calcareous solutions the rock in places becomes amygdaloidal. The fossiliferous limestone which separates the pillows is indurated, but there is no indication of alteration by heat.

The broken-up pillow-lava, which is separated from the rock just described by a thickness of 50 ft. of calcareous tuffs and interstratified limestone, has always been referred to as an agglomerate or breccia; but it is clearly a pillow-lava that has been locally broken up during flow.

The pillows vary much: some are similar to those already described, others are much elongated and almost scoriaceous, the vesicles being abundant and much drawn out. The rock throughout is much more vesicular than the lower lava. One pillow was noticed in which a large central cavity was coated with tachylyte, as well as the periphery. There is great variation in the size of the masses, the smallest having a diameter

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of 6 in., while the largest are as much as 10 ft. across. The material that separates the pillows consists of fragments of pillows that have become broken up; some of the pieces are tachylyte, others have a selvage of tachylyte, while others are free from tachylyte; and this interstitial material is cemented by crystalline calcite. Only in one place does fossiliferous limestone fill the interspaces, and that is in the neighbourhood of a “limestone dyke,” seven or eight of which have penetrated the vertical fissures in the lava. As limestone occurs above the rock, it is more than probable that in this case at least the separating material has come from above. Boulton (1904, p. 158), in describing British pillow-lavas similar in many respects to the present rock, was of the opinion that the limestone came from below.

In places the fragmentary matter makes up most of the rock, with a scattered pillow here and there; elsewhere pillows are massed together and the group is isolated in a matrix of the finer tufaceous-looking material, while the greater portion of the pillows are grouped in a fashion similar to the lower pillow-lava.

The occurrence of fossiliferous limestone between the pillows at Oamaru Cape, together with the fossiliferous tuffs and limestones above and below the lower lava, undoubtedly point to eruption under submarine conditions. The glassy selvage which is everywhere present indicates rapid cooling of the masses, and this would take place in contact with water. The differences in the structure of the two rock-masses just described evidently point to some difference in the mode of eruption. Reid (1907, p. 51) says, “It is still a moot point whether pillow-lavas are true outflows or are intruded sills.” Tempest Anderson (1910, p. 632) witnessed the formation of the pillows as the lava entered the water at Savaii. Geikie (1897) and Teall (1899) ascribe the structure to intrusion into loosely compacted sediments. Benson (1915, p. 125) recognized intrusive contacts with the surrounding sediments in the Nundle district, New South Wales. In the present case the lower lava may be intrusive, but there is no positive evidence to support this view, except the fact that there is no sign of explosive action in the mass, as there is in the upper lava. The indications in the field strongly suggested that the latter rock after coming into contact with the water, and after the invidualization of the pillows, underwent disintegration through local explosions in the mass of the flow, the resulting fragments then settling down through the water and becoming incorporated in the main mass as it flowed over the sea-bottom. After cooling, the rock became fissured, and the subsequently deposited calcareous mud penetrated and filled the cracks, forming dyke-like masses. Pillow-lavas, although frequently occurring as deep-sea lava-flows, are not restricted to conditions of great depth, for Tempest Anderson observed the lava flowing into the sea at Savaii. The nature of the sediments above and below the upper lava at Oamaru clearly indicate shallow-water conditions. In fact, there is reason to believe that the rocks of the Oamaru series were all deposited in comparatively shallow water.

VII. Chemical and Petrographical Notes.

Some preliminary work has been done on the microscopical characters of these pillow-lavas, and chemical analyses made of one of the freshest types from Awamoa Creek near Deborah. More detailed field work is necessary before a full account can be given of these rocks.

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[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Analyses of Pillow-lava, Awamoa Creek.
Inferior of Pillow. Tachylytic Selvage.
SiO2 49.7 50.6
Al2O3 18.6 17.55
Fe2O3 3.2 1.11
FeO 8.15 11.3
MgO 8.62 7.92
CaO 8.2 8.4
Na2O 1.24 1.13
K2O 0.61 0.55
H2O+ 2.25 1.23
100.57 99.79
H2O- 0.79 0.52

The specific gravity of the tachylytic selvage was found to be 2.74, while that of the interior of the pillow was higher, 2.83. This is in accordance with Hutton's results for the similar rock at the lighthouse, his figures being 2.72 and 2.80 respectively (1887, p. 416).

The pillow-lavas at Awamoa Creek (near Deborah) and at the lighthouse near the breakwater show much the same character. In the field there is noticeable on each pillow a distinct black resinous-looking selvage about 1 in. in thickness, while the central portion has all the characteristics of a basalt.

A number of sections have been made from these rocks, and as far as examined they present several features of some interest: it is possible to trace the gradual changes from a basaltic glass with a few phenocrysts, undoubtedly of intratelluric origin, to a holocrystalline dolerite, in which the phenocrysts display a similar attitude towards a completely crystalline ground-mass.

The extreme edge of the tachylyte selvage consists of light brownish-yellow glass in which small porphyritic labradorite crystals and larger crystals of olivine occur as phenocrysts. Skeleton crystals of a basic feldspar also occur, and minute granules of magnetite are scattered sparingly through the glass, which is irregularly fissured. The olivine is almost invariably corroded by the ground-mass, and some of the crystals are penetrated deeply by the glassy base, this being particularly noticeable in the case of the larger ones. Flow-structure is indicated by the parallel alignment of the feldspars. In a section cut farther from the edge the feldspars are bordered by a dark-brown fringe, giving a shadowy extinction between crossed nicols. Under a high power this resolves itself into minute spicules arranged radially around the feldspars. Where the growth has occurred around a minute feldspar there is an approach to a spherulitic arrangement, and an indistinct black cross is seen when the nicols are crossed. It is noticeable that the glass is not bleached on the periphery of this aggregation of crystallites, as is frequently the case in spherulitic tachylytes. Near the centre of the pillow the glass has completely disappeared, and the ground-mass consists of this fibrous brown material shot through with innumerable skeleton feldspars in all stages of growth, the whole enclosing the same minerals that were developed porphyritically in the tachylitic variety of the rock. Still nearer the centre of the spheroid the ground-mass becomes lighter in colour, and rods of magnetite are plainly distinguishable in a faintly

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polarizing base. Another slide from the centre of one of the larger pillows possessed similar characteristics in parts, but augite in bladed ragged forms occupied the same relative position in regard to the feldspars that the spicular growth did in the other sections. The last two varieties of the rock can be paralleled exactly in sections cut from the intrusive rock in Oamaru Creek, west of Hutchinson Quarry. This rock is found to vary in different parts of its mass, however, and a specimen taken from the lower quarry was holocrystalline, and the augite enclosed the feldspars ophitically. The rock shows another variation, in that larger feldspars and olivines are embedded in a mass of granular augite and smaller feldspars. This specimen is much coarser in texture than the other varieties. This granulitic variety of the dolerite is probably due to movement towards the end of the process of consolidation, while the ophitic type indicates that the cooling took place under quiescent conditions.

Pillow-lavas invariably belong to the group of intermediate or basic igneous rocks. Among the Palaeozoic rocks well-developed pillow-lavas are of frequent occurrence in Great Britain and are known as “spilites.” These rocks are characterized by their richness in soda and poverty in potash, and mineralogically by the abundance of a soda-feldspar. Albite is the principal constituent, next in importance is augite, and olivine occasionally occurs. There is frequently a glassy base, occasionally the feldspars are microporphyritic, and often those of the ground-mass have pointed or acicular forms. Sometimes they consist almost wholly of feldspar laths with a fluidal arrangement. In some types the augite may occur as irregular masses enclosing the ends of feldspar rods, producing a subophitic structure. Diabases, representing the intrusive magma, invariably occur with these rocks. Flett (1911, p. 246) considers that the characteristic feldspar of these rocks, albite, is due to the action of pneumatolytic emanations containing water with soda and silica in solution upon the basic feldspars soon after the rocks had solidified. Further, he states that the spilitic suite of rocks are essentially rocks of districts that have undergone a long-continued and gentle subsidence.

The Tertiary pillow-lavas at Oamaru contain no albite, and this is confirmed by chemical analysis, which shows that the present rocks are remarkably poor in soda, but, like the spilites, remarkable for their poverty in potash. Their structure and mineralogical composition can be paralleled in the spilites, except, of course, for the absence of albite. The rocks were erupted under submarine conditions, but the water was shallow. The association with the intrusive olivine dolerite is analagous to the association of variolitic pillow-lavas with diabases in Anglesey and Cornwall. Yet the poverty of the rock in soda precludes its classification as a spilite.

VIII. Conclusion.

1.

There are three horizons of igneous rocks—the Waiareka tuffs, Kakanui breccia, and the upper pillow-lava—although the latter two were almost contemporaneous, the breccia being the earlier.

2.

The stratigraphical unconformities and “limestone conglomerate” may be explained on the assumption that volcanic islands were rapidly formed and rapidly destroyed.

3.

The unconformities introduced into the sequence by former observers are merely local, and of no significance in classification.

4.

The Oamaru series is otherwise conformable throughout.

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5.

The Oamaru pillow-lavas, like similar rocks in other parts of the world, owe their peculiar structure to eruption and solidification under submarine conditions.

6.

These rocks, though similar in some respects to British Palaeozoic pillow-lavas, are clearly differentiated from them by their poverty in soda.

7.

The structural and lithological resemblances of the upper pillow-lava at the lighthouse and the pillow-lava in Oamaru Creek are sufficiently strong to justify the assertion that they are at the same horizon. The succession of rocks at the latter place and at Hutchinson Quarry is similar from the lava to the top of the Hutchinson Quarry greensand. At the breakwater we get a clear succession of the beds below the lava down to the tuffs. At the Rifle Butts we get a sequence from the Awamoa mudstone down to the tufaceous rocks. Piecing the evidence together, it would seem that the top of the thicker limestone at the Rifle Butts represents the horizon of the upper pillow-lava, and it is probable that the rocks shown below these in figs. 1 and 2 will be found equivalent. The beds are fossiliferous throughout, and careful and more exhaustive collecting should enable this point to be decided.

8.

The fossiliferous beds below the upper pillow-lava at the lighthouse are not the equivalent of the fossiliferous beds at Hutchinson Quarry, as asserted by former observers, but are separated from the latter by a considerable thickness of lava, tufaceous beds, limestone, and “limestone conglomerate.”

Bibliography.

Anderson, T., 1910. The Volcanoes of Matavanu in Savaii, Quart. Journ. Geol. Soc., vol. 66, pp. 621–39.

Benson, W. N., 1915. The Geology and Petrology of the Great Serpentine Belt of New South Wales, Part iv, Proc. Linn. Soc. N.S.W., vol. 40, pp. 121–73.

Boulton, W. S., 1904. On the Igneous Rocks at Spring Cove, near Weston-super-Mare, Quart Journ. Geol. Soc., vol. 60, pp. 158–69.

Dewey, H., and Flett, J. S., 1911. On some British Pillow-lavas and the Rocks associated with them, Geol. Mag., dec. 5, vol. 8, pp. 241–48.

Geikie, A., 1897. Ancient Volcanoes of Great Britain (ref. to p. 26).

Hector, J., 1866. Reports and Awards of the Jurors, Appendix A, New Zealand Exhibition, 1865, pp. 371–416.

Hutton, F. W., 1887. On the Geology of the Country between Oamaru and Moeraki, Trans. N.Z. Inst., vol. 19, pp. 415–30.

Hutton, F. W., and Ulrich, G. H. F., 1875. Report on the Geology and Goldfields of Otago.

Lister, J. J., 1891. On the Geology of the Tonga Islands, Quart. Journ. Geol. Soc., vol. 47, pp. 590–617.

McKay, A., 1877. Oamaru and Waitaki Districts, Rep. Geol. Explor. dur. 1876–77, pp. 41–66.

—— 1882. Waitaki, Vincent, and Lake Counties, Rep. Geol. Explor. dur. 1881, pp. 56–76.

Marshall, P., 1915. Cainozoic Fossils from Oamaru, Trans. N.Z. Inst., vol. 47, pp. 377–87.

Marshall, P., and Uttley, G. H., 1913. Some Localities for Fossils at Oamaru, Trans. N.Z. Inst., vol. 45, pp. 297–307.

Park, J., 1905. On the Marine Tertiaries of Otago and Canterbury, with Special Reference to the Relations existing between the Pareora and Oamaru Series, Trans. N.Z. Inst., vol. 37, pp. 489–551.

Reid, C., 1907. The Geology of the Country around Megavissey, Mem. Geol. Suru. England and Wales, pp. 1–73.

Teall, J. J. H., 1899. Silurian Rocks of Britain, Mem. Geol. Surv. Great Britain (ref. to pp. 420–31).

Thomson, J. A., 1916. On Stage Names applicable to the Divisions of the Tertiary in New Zealand, Trans. N.Z. Inst., vol. 48, pp. 28–40.

Uttley, G. H., 1916. The Geology of the Neighbourhood of Kakanui, Trans. N.Z. Inst., vol. 48, pp. 19–27.

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Art. VIII.—Geology of the Oamara-Papakaio District.

[Read before the Wellington Philosophical Society, 19th September, 1917, received by Editors, 31st December, 1917; issued separately, 24th May, 1918.]

Contents.

I.

Description of the Area.

II.

Historical Summary.

III.

Aim of this Paper.

IV.

Description of the Sections.

1.

Devil's Bridge.

2.

Grant's Stream.

3.

Water-race Creek.

4.

Landon Creek.

5.

Flume Creek.

V.

Summary.

I. Description of the Area.

The area (about twenty square miles in extent) with which this paper is mainly concerned is the north-eastern corner of the Province of Otago. It is bounded on the north-east by the valley-plain of the Waitaki River, on the south-east by the sea, on the south by a line drawn east and west through one mile north of Oamaru, and on the west by a line drawn due south through Peebles (see fig. 1).

A considerable portion of the district, particularly between the township of Papakaio and Oamaru, is capped by heavy river-gravels and silts; these are evidently the remnant of a formerly extensive plain which sloped to the south-south-east, as the general trend of the streams that drain the area is in that direction. This former surface has been sculptured into well-rounded ridges and hills, attaining an elevation of 650 ft. near Papakaio in the north, and falling to the 350 ft. level in the south-east. In the north-western part of the district the Ngaparan coal-grits, mudstones, and green-sands crop out, and a ridge of quartz gravels in this locality attains a height of over 1,000 ft. Noticeable features of the country south of this ridge are the two well-marked depressions in the vicinity of Tabletop Hill and on the Ardgowan Estate. The Oamaru Creek in flowing over the softer greensands and tuffs of the former locality has by rapid lateral erosion widened its basin considerably, leaving, however, two limestone-capped flat-topped hills standing prommently above the surrounding low-lying area. The stream on leaving this open tract of country becomes much constricted as it flows over the limestone, and at the Devil's Bridge it passes beneath a natural bridge of limestone before it reaches the Ardgowan area, where the softer Hutchinsonian and Awamoan rocks have undergone extensive denudation, forming the second depressed area. The stream then enters the volcanic area north of Oamaru, and its narrow bed is flanked by precipitous cliffs of basaltic rock.

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Fig. 1.—Geological map of the Oamaru-Papakaio district. In the legend the order of superposition is inverted.

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II. Historical Summary.

Although the older Geological Survey did a considerable amount of work in the Oamaru and Waitaki districts of North Otago, little reference has been made to the geology of the Papakaio district.

In 1874 Traill collected fossils at Pukeuri, and Hector (1882, p. 123) assigned the mudstones there to the horizon of the nummulitic beds of the Upper Eocene—that is, he placed them below the Hutchinson Quarry beds. McKay in 1876 made collections at the Devil's Bridge and at Ardgowan. He also examined the limestone at Landon Creek and referred it to the Cretaceo-Tertiary. The volcanic rocks in the watershed between Oamaru and Landon Creek he referred to a horizon higher than the Waiareka tuffs, and rightly ascribed them to the second period of vulcanicity. Park (1905, p. 519), on palaeontological grounds, placed the Pukeuri beds below the limestone, and stated that the limestone at the Devil's Bridge overlay the Hutchinson Quarry beds. Marshall and Uttley (1913, p. 303), on palaeontological and stratigraphical evidence, placed the Pukeuri beds above the limestone—that is, above the Oamaru beds—and the Hutchinson Quarry beds at the Devil's Bridge also above the limestone.

III. Aim of this Paper.

In 1916, in a paper on the geology of the Kakanui district, I gave a detailed succession of the beds of the Oamaru system east of the Waiareka Valley, and that paper gave some of the observations on which the sequence was based. The Waitaki stone of Professor Park was shown to be the Ototara stone in the locality where he had described it.

It is the aim of the present paper to produce further evidence of post-Waiarekan volcanic activity, to give an account of some hitherto undescribed sections in the Oamaru and Papakaio districts, and to show the relationship of the beds to those in the south of the Oamaru district.

IV. Description of the Sections.

It has already been mentioned that gravel deposits form the surface rock over a great part of the country, but the Tertiary beds crop out in the basins of Oamaru and Landon Creeks, and at several places on the Oamaru-Kurow Road. The sequence is usually clear, but at Papakaio the beds are faulted, and the continuity of an otherwise excellent section is broken.

In the Devil's Bridge area the deposition of the limestone appears to have been continuous from the close of the Waiarekan period to the commencement of the Hutchinsonian; in the other localities to be described, deposition was interrupted by a recrudescence of vulcanicity. It is proposed, therefore, to give an account of the Devil's Bridge section, to be followed by descriptions of sections in the district that show important departures from the normal sequence as represented in that area.

1. Devil's Bridge. (Fig. 2.)

Fig. 2 represents a section from the Devil's Bridge in a west-north-west direction to a point about a mile beyond the area mapped, so as to include the Waiarekan beds.

The tuffs (a) are very fine and tachylytic, and are interbedded with bands of diatomaceous earth. Dykes and sills intersect the tuffs and the

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diatomaceous earth, and the latter is altered in places to a hard flinty rock. There are inclusions of quartz in the dolerite, this being a noticeable feature of the earlier intrusive rocks associated with the Waiareka tuffs. The quartz has probably been incorporated during the passage of the molten rock through the quartz grits that lie at the base of the Tertiary series. The limestone is poor in fossils, and is similar to the building-stone, but in parts it becomes chalky. A peculiar nodular surface marks the junction of this rock with the overlying greensand, although it is not so conspicuous in this locality as in other parts of the district. The green-sand (c) overlying is glauconitic, casts of Foraminifera being plentiful. Some distance above the base Pachymagas parki (Hutt.) occurs in abundance, other fossils being scarce. The brown sands (d) are also glauconitic and very fossiliferous. The nodular band contained Terebratula sp., Aetheia gualteri (Morris), Hemithyris sp., and stems of Isis. The greensand (c), in addition to Pachymagas parki (Hutt.), contained Pecten huttoni Park. The fossils from the brown sands (d) have been recorded by Marshall and Uttley (1913, p. 303) and clearly indicate that the beds are Awamoan.

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Fig. 2.—Section (diagrammatic) W.N.W.-E.S.E. through the Devil's Bridge. (a) Tuffs and diatomaceous earth, intruded by dolerite (a1); (b) limestone; (c) greensand; (d) Awamoa beds; (e) gravels.

Park (1905, p. 518), in describing the beds here, placed the limestone above the Hutchinsonian and Awamoan; but the greensands lie hard upon the surface of the limestone, which is undoubtedly the Ototara stone. The rocks are conformable throughout, and dip towards the coast at an angle of from 10° to 16°.

2. Grant's Stream, Ardgowan. (Fig. 3.)

At Ardgowan, near the junction of Grant's Stream with the Oamaru Creek, a small section is exposed on the roadside. The lowest beds (a) consist of a brecciated pillow-lava, which can be traced in a continuous section along the banks of Oamaru Creek to the town of Oamaru. This bed is overlain by a limestone (b) 10 ft. thick, containing occasional water-worn masses of decomposed vesicular basaltic rock. This passes into an indurated limestone (c), which becomes nodular at its junction with the greensand (d). The nodular portion contains many fossils, but chiefly as casts. Stems of Mopsea also occur. The actual junction with the overlying greensand (d) is not seen, as the latter occur separated from the main exposure. From the nodular surface of the limestone I obtained the following forms: Turbo sp.; Polinices sp., Turritella sp., Lima lima (L.), Ostrea sp., Cardium sp., Liothyrella boehmi Thomson, Terebratulina suessi (Hutt.), Aetheia gualteri (Morris), Hemithyris sp. The section is interesting as it indicates clearly the horizon of the volcanic rocks, which are here about 20 ft. below the nodular bed.

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Fig. 3.—Section at Ardgowan. (a) Brecciated pillow-lava, & c.; (b) limestone (with rounded boulders); (c) limestone; (d) greensand; (e) gravels.

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3. Water-race Creek, Oamaru District. (Fig. 4.)

This creek is a tributary of Landon Creek. The rocks cover an area of about half a square mile, and the exposure is isolated, but it is quite possible to determine the horizon of the upper beds. The section is noteworthy, as it shows a bed of limestone of considerable thickness between two beds of fragmental volcanic rocks. The beds dip E. 30° S., at an angle varying from 10° to 16°.

The tuffs (a) are greenish-brown, much weathered, and cemented by crystalline calcite. They are finer than the breccia higher in the section, and do not contain the same variety of minerals. The limestone (b) is tufaceous in parts, sometimes containing distinct bands of calcareous tuff.

Bed (c) is a thick breccia similar in character to the “mineral breccia” of the Kakanui locality (cf. Uttley, 1916, p. 20). This is overlain by a limestone which becomes glauconitic and fossiliferous towards the top. The fossils obtained were: Epitonium lyratum (Zitt.), Pecten delicatulus Hutt., P. polymorphoides Zitt., Liothyrella boehmi Thomson, L. landonensis Thomson, Murravia catinuliformis (Tate), Terebratulina suessi (Hutt.), Pachymagas ellipticus Thomson, Rhizothyris rhizoida (Hutt.), Hemithyris sp., Aetheia gaulteri (Morris).

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Fig. 4. — Section, Water-race Creek, Oamaru District. (a) Tuffs; (b) limestone; (c) calcareous mineral breccia; (d) limestone, glauconitic and fossiliferous in its upper portion; (e) limestone band; (f) greensand; (g) hard brachiopod band; (h) river gravels.

This bed is followed by a very hard white limestone (e) about 18 in. thick.

The greensand (f) overlying is crowded with brachiopods. The following fossils were collected here: Pecten hutchinsoni (Hutt.), P. huttoni (Park), Epitonium lyratum (Zitt), Pachymagas parki (Hutt.), Rhizothyris rhizoida (Hutt).

The bed (h), which is really the upper portion of (g), is a hardened glauconitic stone. It contained Pachymagas parki (Hutt.) and Pecten huttoni (Park).

This greensand (g) and (h) evidently represents the Hutchinson Quarry greensand, while the hard limestone band (e) represents the nodular band at Kakanui and All Day Bay (cf. Uttley, 1916, pp. 20, 21, 23).

4. Landon Creek, Papakaio Survey District. (Fig. 5.)

About a mile west of Trig. Station B, limestone and greensand occur on both banks of Landon Creek. The section across the creek is shown in fig. 5. The beds dip S. 30° E. at 8°, and this would take them beneath the Awamoa beds at Pukeuri cutting.

The lowest bed is a calcareous tuff, which, however, is not exposed in section. The material excavated from the tunnel for the Oamaru—Papakaio water-race is a tuff, and from the position of the tunnel it must lie beneath the limestone. This limestone is at least 50 ft. thick. It is pure and white in it lower portion, but in its upper 20 ft. it becomes glauconitic, and near the junction with the overlying greensand (c) there is an alternation of

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hard limestone with looser glauconitic sand, giving the rock a flaggy appearance. At their base the greensand (c) is intermingled with limestone, and where the former has been removed by weathering an irregular nodular surface is exposed on the surface of the limestone.

From the upper glauconitic portion of the limestone (b) I collected the following forms: Liothyrella boehmi Thomson, L. landonensis Thomson, Terebratulina suessi (Hutt.), Pachymagas ellipticus Thomson, Rhizothyris rhizoida (Hutt.), Aetheia gualteri (Morris), and Hemithyris sp.

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Fig. 5.—Section, Landon Creek, Papakaio district. (a) Tuffs; (b) limestone; (c) greensand; (d) hard glauconitic band; (e) river gravels.

The greensand (c) yielded Epitonium lyratum (Zitt.), Pecten polymorphoides Zitt., Terebratulina suessi (Hutt.), Pachymagas parki (Hutt.), Rhizothyris rhizoida (Hutt.), Aetheia gualteri (Morris), Hemithyris sp., and Mopsea hamiltoni (Thomson) (?). A hard glauconitic band (d) overlies, containing Pachymagas parki (Hutt.) and Rhizothyris rhizoida (Hutt.).

The sequence in this locality differs somewhat from the section in Water-race Creek, for the breccia is missing, and the hardened limestone in the latter locality is apparently represented by the flaggy limestone in the present section, and the latter is evidently at the horizon of the nodular band in the Kakanui locality.

5. Flume Creek, Papakaio District. (Fig. 6.)

This section is exposed near the township of Papakaio in a small gully, spanned by the flume of the water-race. The section is not continuous, and the dip of the rocks in the lower part of the creek varies somewhat. There are distinct signs of faulting in the neighbourhood. At the head of the gully a bed of diatomaceous earth crops out, and lower down a small exposure on the left shows the same bed lying beneath a fine calcareous tachylytic tuff, dipping N. 70° E. at 20°. Greenish-brown laminated tuffs (c) overlie, and then follows a flaggy limestone (d). There is a break in the section at this point, but tuffs containing minerals occur in situ at the bottom of the bank. Then follows a coarser and more glauconitic limestone, which has a steeper dip than the lower flaggy limestone. A hard band of limestone (g) about 15 ft. thick caps the more glauconitic stone. Greensand (h) lies hard upon (g), and the junction is marked by the great abundance of the stems of Mopsea.

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Fig. 6.—(a) Diatomaceous earth; (b) tachylyte tuff; (c) fine laminated tuffs; (d) limestone; (e) tuffs; (f) glauconitic limestone; (g) hardened limestone; (h) green-sand; (F) fault.

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The greensand yielded Epitonium lyratum (Zitt.), Terebratulina suessi (Hutt.), Pachymagas parki (Hutt.), Aetheia gualteri (Morris), and Hemithyris sp.

In this locality also we have the nodular band occurring at the base of the greensand, and notable for the abundance of alcyonarian stems. Dr. Thomson informs me that a nodule collected by him from this locality was analysed by Mr. B. C. Aston and showed 1.8 per cent. P2O5, equivalent to 2.9 per cent. Ca3P2O8.

V. Summary.

  • (a.) There has been at least one period of vulcanicity subsequent to the Waiarekan tuffs. It is more than probable that there were two periods of eruption, the mineral breccia of Kakanui being the record of the first, while the volcanic rocks at Grant's Creek indicate the last phase. This is not so evident in the present area, as nowhere are the two types of volcanic rocks represented in the same section, although the breccia at Water-race Creek is certainly farther down in the limestone than the volcanic rocks at Ardgowan. In the town of Oamaru, however, the intrusive rocks cut across interbedded limestone and breccia beds.

  • (b.) The mineral breccia of Kakanui (see Thomson, 1906) extends into the Papakaio district, and forms a well-marked stratigraphical horizon throughout the whole Oamaru coastal district.

  • (c.) The diatomaecous-earth deposits occur at Papakaio associated with tachylite tuffs, as in the earlier known deposits in Cave Valley. This represents a considerable extension of its range.

  • (d.) The nodular band is persistent throughout the Oamaru and Papakaio districts from Kakanui to Papakaio, a distance of about twenty miles, and is phosphatic at both these localities. As a hardened band of limestone often underlies it, and has been proved phosphatic by Morgan (1915) at Hutchinson Quarry, it may reward investigation elsewhere.

  • (e.) In the Papakaio district there is no evidence of two distinct limestones separated by the Hutchinson Quarry and Awamoa beds, as contended by Park (1905).

  • (f.) Dr. Thomson informs me that the fauna beneath the Maerewhenua limestone, farther up the Waitaki Valley, bears a strong resemblance to that of the upper part of the Ototara stone in the Landon Creek area. Detailed stratigraphical work between Papakaio and the Maerewhenua districts should therefore go far towards settling the vexed question of the relationship between the Oamaru and Waitaki stones. There are many excellent natural sections in the Maerewhenua district that have not yet been described.

Bibliography.

Hector, J., 1882. Index to Fossiliferous Localities in New Zealand, Rep. Geol. Explor. dur. 1881, pp. 118–28.

McKay, A., 1877. Oamaru and Waitaki Districts, Rep. Geol. Explor. dur. 1876–77, pp. 41–66.

Marshall, P., and Uttley, G. H., 1913. Some Localities for Fossils at Oamaru, Trans. N.Z. Inst., vol. 45, pp. 297–307.

Morgan, P. G., 1915. Phosphate Occurrences in the South Island, 9th Ann. Rep. (n.s.) N.Z. Geol. Surv., pp. 97–98.

Park, J., 1905. On the Marine Tertiaries of Otago and Canterbury, with Special Reference to the Relations existing between the Pareora and Oamaru Series, Trans. N.Z. Inst., vol. 37, pp. 489–551.

Thomson, J. A., 1906. The Gem Gravels of Kakanui, Trans. N.Z. Inst., vol. 38, pp. 582–95.

Uttley, G. H., 1916. The Geology of the Neighbourhood of Kakanui, Trans. N.Z. Inst., vol. 48, pp. 19–27.

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Art. IX.—Descriptions of New Species of Lepidoptera.

[Read before the Otago Institute, 9th October, 1917; received by Editors, 22nd December, 1917; issued separately, 24th May, 1918.]

Hydriomenidae.

Hydriomena canescens n. sp.

♂. 29 mm. Head, palpi, thorax, and abdomen rather dark grey. Antennae, ciliations 1. Legs grey, tarsi annulated with ochreous-white. Forewings triangular, costa subsinuate, apex obtuse, termen subsinuate, oblique, brownish-grey; a broad curved basal band obscurely paler; veins interruptedly blackish; second line thin, obscure, ochreous, anteriorly margined with white; indications of alternate ochreous and white lines between this and termen; a black line round termen, interrupted by ochreous dots on veins: cilia dark grey with a faint paler median line. Hindwings whitish-grey, darker terminally; numerous alternate waved darker and paler lines; terminal area and cilia similar to forewings.

Near H. hemizona Meyr., but the ground-colour is wholly different, and there are many minor distinctions.

Queenstown, in March. A single specimen taken by Mr. M. O. Pascoe, in whose collection the type remains.

H. praerupta n. sp.

♂. 33–34 mm. Head yellowish-green. Palpi yellowish-green mixed with brown. Antennae brown, ochreous-tinged. Thorax yellowish-green mixed with black. Abdomen ochreous. Legs ochreous-grey, more or less infuscated. Forewings triangular, costa moderately arched, apex obtuse, termen slightly bowed; yellowish-green; markings dark olive-green; a curved irregular band near base, preceded by an obscure line; space between basal and median bands pale ground-colour with suffused dark median area; median band broad, anterior margin curved, with strong indentations above and below middle, posterior margin irregularly curved, with strong bidentate projection at middle; subterminal line greenish-white, subdentate, broadly margined anteriorly with dark suffusion which almost touches projection of median band, thus nearly interrupting the stripe of pale groundcolour; an oblique dark striga from below apex to terminal line, deliminating a pale subtriangular apical patch; a crenate blackish terminal line: cilia yellowish-green with some dark scales. Hindwings grey-whitish; a waved fuscous median line and several similar but imperfect preceding and following lines; a thin blackish crenate line on termen: cilia ochreous-grey.

Closely related to H. callichlora (Butl.), from which it can be best separated by the pale apical area, the more dentate subterminal line, and the stronger projection of the posterior margin of the median band. The species may be regarded as the mountain representative of callichlora.

Mount Cleughearn, Hunter Mountains. Two males in January, 1916. A single male in Mr. M. O. Pascoe's collection was taken at Lake Howden in November, 1912. Type in coll. A. Philpott.

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Notoreas incompta n. sp.

♂♀. 26–31 mm. Head, palpi, thorax, and abdomen white densely irrorated with black. Antennae black, finely annulated with white, pectinations in ♂ rather short. Legs black, irrorated with white, tibiae and tarsi annulated with ochreous-white. Forewings triangular, costa subsinuate, termen evenly rounded, oblique, white, densely irrorated with black, especially on median band and terminal area; an irregular curved black basal line, median portion mixed with brownish-ochreous; an obscure double dentate evenly-curved black line at ¼; median band more or less suffused with ochreous, inner margin waved, regularly curved, outer margin twice angularly projecting above middle, more or less incurved beneath; subterminal line obscure, interrupted, white; veins blackish interrupted with white: cilia white barred with black and with a thin median black line. Hindwings greyish-fuscous, terminal area dark fuscous; a pale median fascia and some obscure darker lines on apical half; in some specimens the median area is tinged with brownish-ochreous: cilia as in forewings. Undersides grey-whitish, terminal area broadly fuscous; a black discal dot; some obscure waved dark lines before middle; a prominent waved irregularly-curved black line beyond middle; subterminal line more distinct than on upper surface.

Hardly distinguishable in coloration from N. orphnaea (Meyr.), but easily separable by the shorter antennal pectinations and the lesser development of the palpal hairs. It is considerably larger than N. anthracias (Meyr.), and the markings are less clearly defined.

I am indebted to Mr. R. Gibb, Curator of the Southland Museum, for the opportunity of describing this interesting form, two of each sex having been taken by him on the Kepler Mountains, at an elevation of about 3,000 ft., in January. Types, ♂ (1483) and ♀ (1484) in coll. Southland Museum.

Pyraustidae.

Scoparia declivis n. sp.

♂. 28–32 mm. Head, palpi, and thorax brown densely sprinkled with white. Antennae brown. Abdomen pale whitish-ochreous, grey beneath. Legs grey mixed with fuscous, tarsi with pale annulations. Forewings elongate, triangular, costa hardly arched, subsinuate, apex obtuse, termen almost straight, rounded beneath; fuscous-brown irrorated with white; basal area to first line rather pale; first line whitish, straight, outwardly oblique; stigmata obscure or obsolete; reniform represented by a dark transverse mark; second line curved, deeply indented beneath costa, white; subterminal broad, parallel to termen, suffused, whitish; a series of indistinct dark dots round termen: cilia grey with two fuscous lines. Hindwings pale whitish-ochreous: cilia pale whitish-ochreous with two darker lines.

A browner species than S. petrina (Meyr.), and differing also in the straight first line.

The type specimen was taken at Commissioners Creek (Wakatipu) in February by Mr. W. G. Howes. I have also an example from Macetown, taken, also in February, by Mr. H. Hamilton.

Scoparia scripta n. sp.

♂♀. 29–32 mm. Head ochreous-grey-whitish. Palpi moderate, maxillaries white, labials white within, brownish-black without. Antennae ochreouswhitish, ciliations in ♂ ¾. Thorax brownish – grey. Abdomen ochreous-whitish. Legs ochreous-white, much infuscated, tarsi banded with fuscous.

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Forewings elongate, triangular, costa subsinuate, apex subacute, termen sinuate, slightly oblique, rounded at tornus; pale ochreous densely sprinkled with fuscous and more or less suffused with white on costal half; a thick black basal streak from costa, curving to centre of wing, thence straight to about ¼, apex acute; first line faintly whitish, posteriorly fuscous-margined, from costa at ¼ strongly outwardly oblique for about ⅔, thence sharply angulated to dorsum before middle; orbicular large, touching first line, oval, black, pale-centred, lower half thick, prominent, upper half hardly traceable; claviform obsolete; reniform irregularly X-shaped, large, black, upper and lower halves filled with fuscous, inner lower arm produced so as sometimes to touch orbicular; second line indistinctly whitish, preceded by a series of cuneate black dots, sharply indented beneath costa; a series of roundish black dots on termen: cilia ochreous mixed with fuscous; two indistinct darker lines. Hindwings pale whitish-ochreous; lunule, subterminal line, and terminal band infuscated: cilia as in forewings but rather paler.

Closely related to S. rotuella (Feld.) and S. clavata Philp. From the former it may be distinguished by the disconnected orbicular and reniform, and from the latter by the acutely pointed basal streak.

Hunter Mountains, in January. Four males and one female taken in damp gullies at about 3,000 ft

Scoparia caliginosa n. sp.

♂. 17 mm. Head, palpi, antennae, and thorax ferruginous-brown mixed with grey. Abdomen ferruginous-brown. Legs grey-brown, tarsi obscurely annulated with paler. Forewings moderate, triangular, costa almost straight, apex obtuse, termen straight, slightly oblique, ferruginous-brown densely irrorated with whitish on basal ¾; a short oblique brown fascia from costa at base; first line obscurely paler, curved, indented at middle, suffusedly margined posteriorly with ferruginous-brown; orbicular indistinct; claviform irregular, blackish on fold; reniform obscurely 8-shaped, ferruginous-brown, pale-centred; second line parallel to termen, subsinuate, interruptedly margined with ferruginous-brown anteriorly, whitish; subterminal line close to termen, indistinct, whitish; cilia fuscous-grey with darker basal line. Hindwings fuscous-grey, darker terminally: cilia grey with two darker lines.

Near S. ergatis Meyr. and S. organaea Meyr., but separated from both by the form of the second line.

A single male received from Mr. J. H. Lewis. Locality doubtful, but probably Matakanui.

Tortricidae.

Eurythecta curva n. sp.

♂. 14–15 mm. Head and palpi ochreous. Antennae fuscous, ciliations 2 ½. Thorax whitish-ochreous. Abdomen grey – whitish, anal tuft ochreous. Legs ochreous – whitish. Forewings, costa strongly arched at base, apex round-pointed, termen straight, oblique ochreous-whitish with scattered fuscous scales; a rather bright ochreous mark in disc above middle fromto ⅔; sometimes a similar but more obscure mark below middle; the fuscous scales sometimes tend to form lines on veins: cilia whitish-ochreous with two darker lines. Hindwings, termen markedly sinuate, greyish-fuscous: cilia as in forewings.

Nearest to E. eremana (Meyr.), but differing in size and wing-shape.

Hunter Mountains, in January. Fairly common on low herbage at 3,500 ft.

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Epichorista theatralis n. sp.

♂. 14 mm. Head, palpi, and thorax ochreous. Antennae fuscous, annulated with ochreous towards base. Abdomen fuscous-grey. Legs grey-whitish. Forewings moderately arched at base, apex rectangular, termen almost straight, hardly oblique, rather bright ochreous; markings silvery metallic but rendered obscure by an admixture of ground-colour; a broad fascia from ¼ costa to ½ dorsum; a narrow fascia from ½ costa, strongly outwardly oblique to middle of wing at ¾, thence angled downwards to dorsum before tornus; a slightly curved subterminal line: cilia bright ochreous. Hindwings dark greyish-fuscous: cilia greyish-fuscous with a darker basal line, ochreous round apex.

Apparently nearest to E. emphanes (Meyr.), but entirely different in coloration. A single male being all the material available, the generic position of the species must for the present be regarded as provisional.

Hunter Mountains, in January. The type was secured in Nothofagus forest at about 2,750 ft.

Gelechiadae.

Gelechia sparsa n. sp.

♂. 10–11 mm. Head and thorax white densely mixed with brown. Palpi white, brown beneath. Antennae fuscous with some admixture of whitish. Abdomen fuscous. Legs pale fuscous, tarsi obscurely annulated with whitish. Forewings elongate, narrow, costa slightly arched, apex acute, termen extremely oblique; white densely irrorated with fuscous and ferruginous-brown; an outwardly-oblique ferruginous-brown fascia from middle of dorsum, reaching half across wing; a blotch of similar colour at tornus: cilia grey-whitish sprinkled with fuscous. Hindwings, termen strongly and angularly emarginate, fuscous: cilia fuscous-grey.

Not closely approaching any other Gelechia; perhaps nearest to G. glaucoterma Meyr.

Dunedin, in November. Three males taken by Mr. C. C. Fenwick, whose collection contains the type.

Oecophoridae.

Borkhausenia honorata n. sp.

♂. 12 mm. Head, palpi, antennae, and thorax dark bronzy-brown. Abdomen dark fuscous. Legs fuscous, tarsi annulated with yellow. Forewings moderate, costa moderately arched, apex obtuse, termen rounded, oblique, dark fuscous-brown; a broad yellow stripe along dorsum, indented above before middle and tornus; an irregular yellow blotch beneath costa at ⅓ and a similar one before ⅔, both sometimes absent; a broad straight yellow fascia from costa at ⅘, parallel to termen, reaching ⅔ across wing: cilia fuscous. Hindwings and cilia dark fuscous.

Allied to B. chrysogramma Meyr., but differing entirely in the arrangement of the yellow markings.

Two examples secured in the neighbourhood of Invercargill, and a third at Knife and Steel Boat-harbour (Fiord County). All taken in forest in December. Mr. G. V. Hudson has a specimen from Lake Harris, taken in January, 1906, this being the first of the species to be brought to light.

Borkhausenia sabulosa n. sp.

♂. 10–11 mm. Head, palpi, thorax, and abdomen greyish-brown. Antennae greyish-brown annulated with darker. Legs grey-brown, tarsi obscurely annulated with ochreous. Forewings moderate, in ♀ lanceolate,

– 129 –

costa strongly arched, apex obtuse, termen very oblique, greyish-brown with numerous scattered ochreous scales, especially ininthickly and irregularly sprinkled with fuscous-brown: cilia grey with fuscous sprinkling. Hindwings fuscous-grey: cilia grey with darker basal line.

Approaches B. melanamma Meyr., but is smaller, and differs in the peculiar speckled appearance.

Central Otago. Taken commonly by Mr. J. H. Lewis, to whose liberality I am indebted for the type of the species.

Trachypepla semilauta n. sp.

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

♂ ♀. 15–16 mm. Head ochreous-white. Palpi ochreous-white infuscated at base beneath and with a fuscous band before apex. Antennae fuscous, obscurely annulated with ochreous, ciliations in ♂ 2 ½. Thorax-fuscous mixed with ochreous. Abdomen fuscous-grey. Legs whitish-grey with some infuscation. Forewings rather broad, costa moderately arched, apex subacute, termen almost straight, strongly oblique; white, faintly tinged with yellowish; base narrowly fuscous-black, extending on costa to 1/5; an outwardly-angulated fuscous-black fascia from dorsum at middle, not reaching costa, broadest on dorsum where it is sometimes bright ochreous; a triangular black fascia from costa at ½, its apex, which encloses a white spot, reaching centre of wing, thence continued as a line to tornus; a small black mark preceding this below middle; a curved black fascia from costa at ¾ round termen to tornus, anteriorly margined with white, the space between this and the median fascia being filled with bright ochreous; a black apical blotch; in some specimens the space between the costal fasciae is suffusedly filled with dark fuscous, the ochreous and white colouring being almost obsolete: cilia whitish-ochreous more or less sprinkled with fuscous; apex fuscous. Hindwings dark greyish-fuscous: cilia grey-fuscous with darker basal line.

Distinguished from T. ingenua Meyr., its nearest ally, by the white basal area of forewings.

Hunter Mountains, in January. Three specimens beaten from undergrowth in Nothofagus forest at about 2,750 ft.

Heliodinidae.

Thylacosceles radians n. sp.

♂ ♀. 8–9 ½ mm. Head and palpi shining white. Antennae white, infuscated on apical third. Thorax grey-whitish. Abdomen ochreous-whitish, apical half in ♂ dark fuscous. Legs white, tibial fringe black. Fore-wings moderate, parallel-sided, costa hardly arched, apex acute, termen extremely oblique, leaden fuscous, somewhat ochreous-tinged in ♀; an obscure suffused white blotch in disc at ¾, sometimes preceded by a white spot on tornus: cilia fuscous. Hindwings and cilia grey-fuscous.

Smaller and darker than T. acridomima Meyr.

Seaward Bush (Invercargill). Fairly common in December. T. acridomima is attached to the fern Aspidium aculeatum var. vestitum, and it is possible that the food plant of T. radians is Polypodium diversifolium, which, with other epiphytic growth, frequently covers the trunks of the kamahi.

Gryphipterygidae.

Hieroderis (?) stellata n. sp.

♂. 20mm. Head ferruginous-brown. Palpi dark fuscous, apex of second joint beneath and apex of terminal joint whitish. Antennae

– 130 –

narrowly annulated with ferruginous-brown and white. Thorax, anterior half dark cupreous with purplish sheen, posterior half white. Abdomen greyish-fuscous. Legs fuscous-grey, anterior pair darker, tarsi broadly annulated with white. Forewings, costa strongly arched, apex rounded, termen subsinuate, little oblique, rounded beneath; shining cupreous; markings white; an irregularly-triangular basal patch on lower half of wing, its upper edge indented; a round spot beneath costa at ¼; a chain of small spots from costa at ½ curving round to costa at ⅝; an inwardly-oblique series of two or three spots from costa at ⅞; a dot on costa before apex; a large triangular patch on dorsum before middle, its apex reaching to centre of wing and its base broadly bifid; a round spot on dorsum at ½, followed by a series of spots which curve round to tornus: cilia cupreous with white patches beneath apex and at tornus. Hindwings elongate-ovate; dark fuscous: cilia paler, with obscure dark basal line and tips whitish round apex.

Very handsome and distinct. The generic position is provisional; the species probably belongs to a genus not hitherto recorded from New Zealand.

Blue Cliff (Fiord County). A single specimen taken in January by Mr. C. C. Fenwick. It was captured in a bush track after dark. Type in coll. C. C. Fenwick.

Glyphipteryx barbata n. sp.

♂. 15–20 mm. Head and thorax fuscous-grey. Palpi fuscous-grey, second joint with dense rounded tuft of long hair. Antennae blackish. Abdomen fuscous-grey, segmental divisions and anal tuft paler. Legs fuscous-grey, tarsi annulated with fuscous and whitish. Forewings elongateovate, costa strongly arched, apex acutely projecting, termen extremely oblique; fuscous-grey with faint brassy sheen; a white median stripe from base to beneath apex, becoming obsolete towards extremities; apical ⅓ of costa more or less whitish with three or four dot-like strigae near apex: cilia fuscous-grey with obscure darker basal line. Hindwings fuscous-grey: cilia fuscous-whitish, paler round apex.

Superficially very like G. bactrias Meyr., but at once distinguished by the tufted palpi.

Discovered by Mr. C. E. Clarke, who found it fairly common at Waitati (Dunedin) in November. Type in coll. C. E. Clarke.

Hyponomeutidae.

Zelleria rorida n. sp.

♂. 13–15 mm. Head and palpi white densely sprinkled with ochreous. Antennae brown. Thorax white mixed with ochreous. Abdomen grey-whitish. Legs grey-whitish, anterior pair infuscated. Forewings elongate, of uniform breadth, costa slightly arched, apex subacute, termen very oblique, pale greyish-ochreous irrorated with blackish-brown, an irregular interrupted white suffusion along dorsum, continued up lower half of termen; three series of blackish-brown spots from base to termen, sometimes more or less obsolete, first on costa, second on upper median vein, third on lower median; sometimes a similar series below fold; a broad inwardly-oblique brown fascia from costa to dorsum at ⅓; a semi-oval brown spot on dorsum at ½; an irregular white blotch on costa near apex: cilia ochreous-grey, brown round apex. Hindwings grey: cilia ochreousgrey

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Differs from Z. sphenota (Meyr.) in the presence of the preapical white blotch.

Bluff and Invercargill, in coastal forest; a male and female in November. Mr. J. H. Lewis has taken the species in Central Otago.

Plutellidae.

Dolichernis jubata n. sp.

♂. 14.mm. Head ochreous. Antennae ochreous, annulated with fuscous. Palpi ochreous mixed with brown, terminal joint brownish. Thorax ochreous, shoulders brownish – black. Abdomen ochreous – grey. Legs ochreous-grey, anterior tarsi fuscous annulated with ochreous. Forewings elongate, costa strongly and evenly arched, apex obtuse, termen rounded, oblique; light ochreous; markings blackish brown; a broad stripe along costa, irregular beneath, interrupted before apex, apical spot darker; first discal spot obliquely before plical, touching costal stripe; plical at ½, oviform; second discal transverse, touching costal stripe; a broad fascia along termen, interrupted below apex; numerous scattered dark scales on lower half of wing: cilia ochreous with broad dark basal line. Hindwings grey-whitish: cilia grey with darker line round apex.

Very distinct. The species is placed in Dolichernis pending the discovery of further material; with the exception of the proportionate length of antenna to forewing the characters agree very well.

Tisbury, Invercargill. A single male taken in kamahi (Weinmannia racemosa) forest in January, 1917. Mr. G. V. Hudson has also a single example, taken at Kaeo in January, 1913. Evidently a wide-ranging though scarce species. Type in coll. A. Philpott.

Orthenches polita n. sp.

♂. 11 mm. Head whitish – brown. Palpi white, brownish beneath. Antennae bronzy-brown, broadly annulated with white. Thorax shining dark brown. Abdomen and legs grey-fuscous. Forewings rather long, costa moderately arched, apex obtuse, termen rounded, oblique; shining brassy with cupreous reflections; a large white oviform spot in middle near base; a broad white striga from dorsum at middle reaching half across wing; an irregular white blotch above tornus; a streak of purplish-violet from beneath basal spot along fold to tornus, attenuated at extremities and interrupted at median fascia and before tornus; a similarly coloured but more obscure streak from above median fascia to tornal blotch: cilia grey, darker round apex. Hindwings and cilia grey.

Not closely related to any other Orthenches; perhaps nearest to O. drosochalca Meyr., but quite different in the arrangement of markings.

Invercargill. The type was taken in July, and another specimen was secured in February.

Tineidae.

Sagephora exsanguis n. sp.

♂. 10–12 mm. Head white, face ochreous. Palpi white, apical half of second joint brown. Antennae, thorax, and abdomen white. Fore-wings elongate, narrow, costa moderately arched, apex round-pointed, termen rounded, extremely oblique; white; costa and dorsum broadly pale-brownish throughout reducing ground-colour to a median stripe; apical half of dorsal stripe irregularly margined above with blackish; a few dark scales on costa near apex: cilia concolorous with wing – markings. Hindwings and cilia shining white.

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Differs from the other members of the genus in its pale coloration.

A single specimen taken at Bluff in November, and a few secured by Mr. C. E. Clarke near Dunedin in October, November, and December.

Micropterygidae.

Sabatinca barbarica n. sp.

♂. 10–11 mm. Head rather bright ochreous. Antennae pale ochreous, apical portion black. Thorax ochreous. Abdomen dark greyish-fuscous. Legs ochreous, tarsi annulated with black. Forewings ovate-lanceolate, costa moderately arched, apex acute, termen extremely oblique; pale ochreous; a bright coppery suffusion along dorsum often segregated into one or more spots; base of costa obscurely darker; an interrupted irregular coppery fascia from costa near base to tornus, sometimes including an almost black spot at middle; sometimes one or more coppery spots on costa at ½; three coppery (sometimes blackish) spots on costa at apex, from which an irregular coppery fascia runs towards dorsum, connecting with first fascia above tornus; sometimes a blackish dot on termen at middle: cilia pale ochreous.

Near S. caustica Meyr., but larger and more vividly marked.

Seaward Bush (Invercargill). Eight examples taken amongst low herbage in the forest in December and January.

Art. X.—Descriptions of New Zealand Lepidoptera.

[Read before the Wellington Philosophical Society, 12th December, 1917; received by Editors, 22nd December, 1917, issued separately, 24th May, 1918.]

The material for these notes was received from my esteemed correspondent Mr. G. V. Hudson.

Phycitidae.

Delogenes n. gen.

Tongue developed. Antennae in ♂ shortly ciliated, slightly sinuate and thickened towards base of stalk, basal joint moderate. Labial palpi moderate, subascending, second joint considerably thickened with dense appressed scales, terminal joint very short, obtuse. Maxillary palpi imperceptible. Forewings with 4 and 5 stalked, 9 and 10 out of 8. Hindwings with cell not quite reaching middle; 3 and 4 stalked, 5 absent, 7 out of 6, anastomosing with 8.

This remarkable and interesting genus is a notable addition to the scanty local representation of the family.

Delogenes limodoxa n. sp.

♂. 24 mm. Head, palpi, and thorax grey suffusedly irrorated with whitish. Abdomen whitish – grey, anal tuft ochreous – whitish. Forewings very elongate-triangular, very narrow at base, costa almost straight, gently arched towards apex, apex obtuse, termen slightly rounded, oblique; fuscous, finely and suffusedly irrorated with white; lines dark brown sprinkled with blackish, first rather oblique, nearly straight, dilated towards costa, second

– 133 –

at ⅘ parallel to termen, sharply angulated outwards in middle and inwards above this, marked with a series of short black dashes on veins, and followed by a whitish shade becoming white on costa and edged posteriorly with a series of small dark-fuscous marks; two cloudy brownish sometimes connected spots transversely placed on end of cell; a terminal series of cloudy dark-fuscous dots or marks: cilia light fuscous irrorated with white. Hindwings light grey: cilia whitish-grey.

Waitati (Clarke); two specimens. Superficially this suggests a Scoparia.

Carposinidae.

Carposina sarcanthes n. sp.

♂. 15 mm. Head white, with a few grey specks. Palpi whitish sprinkled with grey, basal half dark fuscous. Thorax grey with a curved white median bar, patagia white with some grey scales. Abdomen pale pinkish-ochreous. Forewings elongate, rather narrow, posteriorly somewhat dilated, costa gently arched, apex obtuse, termen straight, oblique; pale grey, irregularly mixed with white and somewhat sprinkled with dark fuscous; a semi-oval blackish blotch on base of costa; seven dots of blackish irroration on costa between this and apex; two small round grey spots edged beneath with blackish and circled with white beneath costa towards middle; a blackish-mixed tuft edged posteriorly with white in disc at ⅓, one beneath middle of disc, and two on end of cell, discal area between these blackish – sprinkled and without whitish scales; an irregular subterminal series of blackish dots edged posteriorly with white: cilia pale grey irrorated with white. Hindwings whitish-grey, basal half suffused with pale pinkish-ochreous: cilia grey-whitish.

Wellington (Hudson); one specimen. Specially characterized by the pale pinkish-ochreous basal half of hindwings.

Gelechiadae

Epithectis Meyr.

Basal joint of antennae without pecten. Labial palpi with second joint slightly rough beneath, terminal joint nearly as long as second. Forewings with 7 and 8 out of 6. Hindwings nearly 1, trapezoidal, apex pointed, produced, termen sinuate; 3 and 4 connate, 5 somewhat approximated, 6 and 7 stalked.

A widely distributed genus, not previously known from New Zealand.

Epithectis zophochalca n. sp.

♂. 9 mm. Head shining bronzy – metallic. Palpi whitish – bronzy, second joint hardly rough beneath, anterior edge of terminal joint dark fuscous. Thorax purplish-bronzy-fuscous. Abdomen dark fuscous. Fore-wings lanceolate; glossy rather dark bronzy-fuscous; stigmata blackish, plical obliquely before first discal; small cloudy whitish spots on costa before ¾ and on tornus slightly anterior to this, on one wing connected by a faint straight whitish shade: cilia fuscous, round apex with a dark-fuscous antemedian line. Hindwings with apex considerably produced; dark fuscous; a fine longitudinal hyaline line in disc: cilia fuscous.

Auckland, in January (Hudson); one specimen.

Oecophoridae.

Borkhausenia thranias Meyr.

Two examples sent, taken at the Dun Mountain, Nelson, in January (Hudson); one of these is quite like the unique type specimen from

– 134 –

Whangarei (which has cilia of forewings yellow), but the other has the cilia of forewings light grey, giving a quite distinct aspect, as they were taken together, and are alike in all other respects, they are doubtless the same species, but it is an unusual form of variation.

Trachypepla photinella Meyr.

An example in good condition sent by Mr. Hudson shows a well-marked scale-tuft above dorsum of forewings at ¼ (rubbed in all examples previously seen), and therefore the species is referable to Trachypepla, and not to Eulechria as hitherto supposed.

Tineidae.

Endophthora pallacopis n. sp.

♂. 12 mm. Head white. Palpi white, externally dark fuscous. Thorax pinky-whitish sprinkled with fuscous (partly defaced). Abdomen light grey. Forewings narrowly elongate lanceolate; 7 and 8 stalked; pinky-whitish, with scattered light olive-brown scales; a slender blackish streak along costa from base to near ⅓, edged beneath by a light olive-brownish streak; a black basal dot in middle, and one on lower edge of this streak towards apex; some scattered black scales along dorsum, a blackish mark on costa before middle, edged beneath by a light olive-brown spot connected anteriorly with a similar spot beneath it in disc by a transverse-linear black dot; a blackish mark on costa at ⅔, with a light olive-brownish spot adjoining it beneath; an irregular light olive-brownish spot on tornus, and one resting on termen below middle: some black irroration along termen; two irregular blackish dots on costa near apex cilia whitish, basal half suffused with light grey and slightly sprinkled with blackish. Hindwings light grey: cilia whitish-grey.

Wellington, in December (Hudson); one specimen.

Micropterygidae.

Sabatinca eodora n. sp.

♂. 10 mm. Head, palpi, and thorax fulvous. Antennae ochreous, with a black band of three joints above middle and another of three or four joints beneath apex. Abdomen blackish-grey. Forewings suboblong, costa rather abruptly arched anteriorly, then nearly straight, slightly arched towards apex, apex obtuse, termen slightly rounded, rather strongly oblique; light rosy-pink, more or less sprinkled or suffused with grey except on basal third; basal third orange – fulvous, including a bright – yellow transverse blotch edged with a few black scales from costa at ¼; a yellow dot edged with black on dorsum before middle; a somewhat oblique bright-yellow fasciate blotch from middle of costa reaching half across wing, edged with a few black scales and margined with orange-fulvous continued as an orange-fulvous fascia to dorsum beyond middle, its anterior margin marked with a yellow black-edged dot below middle and a black mark on dorsum; an irregular narrow orange-fulvous fascia from ¾ of costa to tornus, partially edged with black scales, and marked with two or three small variable yellow dots; two small yellow anteriorly black-edged spots on costa towards apex and two on termen: cilia yellow barred with grey, base tinged with rosy. Hindwings deep purple, becoming dark grey anteriorly: cilia dark grey, on costa with two indistinct pale-yellowish bars.

Shedwood Forest, Tapawera, near Nelson, in January (Hudson); four specimens. A very elegant and distinct species.

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Art. XI.—Notes from Canterbury College Mountain Biological Station, Cass.
No. 6. — The Insect-Life.

[Read before the Canterbury Philosophical Institute, 5th September, 1917; received by Editors, 31st December, 1917; issued separately, 24th May, 1918]

Introduction.

The general descriptions which have been written of the physiography and plant-associations in the neighbourhood of the station are essential starting-places for, as well as stimulants to, more detailed study. With the object of preparing a similar paper on the insect-life near the station I made some collections during the summer and autumn of 1917, and arranged the specimens thus captured in a small museum case deposited at the station for reference by future students. The notes on the collection were at first intended to be purely systematic, but it was soon recognized that the insects were so noticeably a part of the landscape that they should be dealt with in the order of their occurrence rather in that of their zoological classification. Thus on tussock or in swamp or forest different associations of insects are found, and in the following pages these associations are described, and in some cases attempts are made to explain their relationships to their environment. Of course, in dealing with several orders of insects no attempt at a complete catalogue can be made even when only a small area is under consideration, and so these notes deal only with the species that from their size or numbers come readily under the observation of the student.

A. The Environment.

The topography and physiography of the neighbourhood of the station are described by Chilton* and Speight. The variation in land and water is such as to encourage a great diversity of insect-life. Within a radius of little more than a mile from the station there are a lake, a swamp, a sluggish stream, many rapid streams, a shingly river-bed, a stretch of open tussock country, open shrub-land, shrubby thicket, patches of forest, and areas of bare rock, with slopes of scree. Each topographic form is in general associated with a special kind of plant-covering, and this, of course, forms the dominant factor in the environment of the insect population. The plant-associations are described by Cockayne and Foweraker, and such a description is essential as a basis for any attempt at detailing the modes of life of the insects.

The plant-life of the area is to a certain extent unaltered by the advent of man. The forest, the shrub-land, and the river-bed and rock plants are probably almost entirely primitive. Even the tussock-land has been altered but little, and the alteration that has occurred seems more in the direction of varying the proportions of the primitive plants than in their replacement by introduced species.

[Footnote] * C. Chilton, Notes from Canterbury College, Mountain Biological Station, No. 1′ Trans. N.Z. Inst., vol. 47, p. 331, 1915.

[Footnote] † R. Speight, ibid., vol. 48, p. 145, 1916.

[Footnote] ‡ L. Cockayne and C. E. Foweraker, ibid., vol. 48, p. 166, 1916.

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Hypochaeris radicata, however, is found all over the open country, and is freely visited by the small bee Dasycolletes hirticeps. Trifolium minus, too, which occurs in the gullies, is probably visited by some insect, as it sets seed freely, and the seeds have been germinated from sheep-dung. These are the only cases noted where change of vegetation may have influenced insect-habits.

In the animal world, however, or at least in the vertebrate world, the most profound changes have been made. Over practically the whole of the area the sheep reigns supreme, and the effect of its grazing upon certain flowers has doubtless been reflected on the insect population. With the sheep has been introduced Oestrus ovis, the sheep's nasal bot-fly, which lays its eggs in the sheep's nostrils, so that on hot days the persecuted beasts may be seen stamping their feet, tossing their heads, or standing huddled together with noses to the ground. Sheep's dung, too, must be fed upon by numerous maggots and beetles, and the animals that die have a marked effect upon the numbers of blow-flies that infest this and all similar localities. Except the sheep, the only mammal that could affect the vegetation is the hare, and of this only occasional specimens are seen. Bird-life is not at all plentiful, and has probably changed considerably as a result of human occupation. Of water-birds, the paradise duck (Casarca variegata) is the most common, flocks of twenty or thirty being frequently seen on Lake Sarah and in the swamps. Grey ducks (Anas superciliosa) and a very few black swans also occur on the lake. An odd pukeko (Porphyrio melanonotus) may be seen in the swamp, and an occasional shag (Phalacrocorax carbo) passes from stream to stream. The black-cap tern (Sterna albistriata) and the seagull (Larus dominicus) are rather common on the river-beds. Of native land-birds the grey warbler (Pseudogerygone igata) is the commonest in shrub-land and forest-skirt. The kea (Nestor notabilis) occurs in flocks of ten to twenty above the line of about 4,000 ft., and traces of its scratching for earth-boring insects are frequently seen. The banded dotterel (Ochthodromus bicinctus) is common on the river-beds, an occasional hawk (Circus gouldi) nests in the swamps, and very rarely a morepork (Ninox novae-zealandiae) may be heard from the patches of forest. Introduced birds are much more numerous. The skylark (Alauda arvensis) is found everywhere, and a nest with eggs was seen among the rocks at an elevation of nearly 5,000 ft. Skylarks are in this locality almost purely insectivorous, though in the agricultural districts poisoned grain scattered over a field of sprouting wheat kills more larks than sparrows. The house-sparrow (Passer domesticus) and starling (Sturnus vulgaris) build about the railway-station, but, while the sparrow keeps near the buildings, the starling may be seen a mile away on the rocks and the tussock-land. Thrushes (Turdus musicus), blackbirds (T. merula), red-polls (Linota rufescens), and, most of all, yellowhammers (Emberiza citrinella) have invaded the shrub-land, and doubtless exert a considerable effect on the insect-life.

It seems likely that birds were once much more numerous than they are at present. This opinion is based upon two facts: (1) The development of protective coloration among all orders of insects is very perfect, and seems much more elaborate than is necessary to escape the meagre army of enemies now present. Further, many insects are abandoning (or, it may be, had never acquired) the habits that would conduce to safety from bird-attack. Crambus flexuosellus, the common yellowy-white moth of the tussocks, is a familiar example. While stationary it is invisible, but it rises before the walker at every step, and its movement when disturbed

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would soon lead to its extermination if there were a hungry insectivorous-bird population. The highly protectively coloured Scoparia philerga of the forest-glades is quite invisible as it sits at rest on the trunks of the beech-trees, but if one walks noisily forward the moth will fill the air in its fluttering hundreds. It is true that in both these cases the kind of noise demanded is not that associated with a bird-attack, and the short zigzag flight and quick settling may lead to escape from other dangers. Still, protective coloration and the crouching habit are nearly always associated, and in many insects at Cass that association does not exist. (2) The second fact indicating a more plentiful bird-life in the past is the great profusion of berries and drupes borne by the shrubs. The close connection between the presence of birds and the production of succulent fruits is denied by Guppy,* but his views do not appear to have received wide acceptance. The writer's view is that if there were no frugiverous animals, then the characteristic of producing brightly coloured, fleshy, and palatable fruits would not have been fixed in so high a degree as is commonly found, and that a large number of plants bearing such fruits is evidence of a large bird population. The suggestion that frugiverous birds would have no effect on the insect-life is of little weight, as the annual variation in the food of birds is not well known. The variation is probably considerable, as is indicated by the fact that so purely a grain-eating bird as the sparrow feeds its nestlings for about six weeks on nothing but insects. Of more importance is the suggestion that the birds probably visited certain districts only during the fruiting season of the plants they specially favoured, and at that time would almost entirely neglect insects as food.

Except the birds, the only native land vertebrate is the common lizard (Lygosoma moco), which is found not infrequently on the tussock. In the lakes and streams, however, fish, especially trout, are very common, and the introduction of trout must have made an enormous difference to the insect and probably to the bird population of the district. Hudson has shown that the stomachs of 60 trout taken from various localities contained 4,804 Neuroptera, 662 other insects, and 28 other animals. At this rate the reduction of Neuroptera in our streams must be enormous, and, as these insects, while aquatic in their immature stages, are aerial when adult, insect-eating birds may also have suffered a reduction in food-supplies sufficient either to drive them from the neighbourhood or at least to compel them to take to other food. In either case the reaction upon the general insect-life of the district must have been very considerable, and it becomes obvious that the insects are, on the whole, living in an environment that is much changed since the advent of the white man.

Two important factors in the environment are dead sheep and white flowers, for these are correlated with the two most striking features of the insect-life—namely, blow-flies by day and moths by night. The two common blow-flies are Calliphora quadrimaculata, the well-known bluebottle, and C. oceana, which is somewhat smaller, and is covered with bright-yellow hairs below. Both these species occur in hundreds everywhere, and fill the air with their buzzing wherever a human being rests for a few minutes. When a sheep dies the blow-flies are attracted from near and far: each lays a hundred or more eggs upon it, and the resultant maggots are fully fed through their active life. But the thousands of flies thus

[Footnote] * H. B. Guppy, Observations of a Naturalist in the Pacific, vol. 2, p. 99, 1906.

[Footnote] † G. V. Hudson, New Zealand Neuroptera, West and Newman, London, 1904.

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produced do not always find a dead sheep on which to lay their eggs, and therefore they are urgently attracted to any place where there is the faintest scent of animal matter. I have seen C. quadrimaculata so violently impelled to lay her eggs somewhere that she has done so on a bicycle-tire where it had just been pressed with a perspiring hand.

After nightfall the swarms of moths are as insistent as are the blowflies by day. These night-flying honey-suckers are represented by about twenty species, and, as these were obtained chiefly round the lamp in the living-room of the station, definite search would probably double the number of species. Now, the day-flying honey-suckers number only eight species, and the disproportion in individuals is much greater. The entomophilous flowers of the neighbourhood, therefore, must depend chiefly upon night-flying insects, and the colours of their flowers should be most commonly white, or some pale tint, rather than the darker colours of red, blue, or deep yellow.

An examination was made of the list of plants near the station as given by Cockayne and Foweraker, and the colours of such of them as produce nectar were taken from Cheeseman's Manual of the New Zealand Flora. The examination showed that fifty-one native plants were described as having flowers either white, rosy white, or pale blue or white, while only sixteen were described as yellow, red, blue, or brown. Dr. Cockayne has pointed out to me the undeniable fact that, to the human eye at least, white flowers are much more conspicuous even by day than those of any other colour, so that it would probably be quite incorrect to regard every white flower as cross-fertilized by night-flying insects. At the same time, given the nocturnal or crepuscular honey-suckers, it would obviously be advantageous for the plant to have white flowers: abundance of such flowers would encourage the multiplication of the insects that depend on them for their food; so that the large excess of plants bearing white or pale flowers is here regarded as an important factor in the character of the insect population.

B. The Insect-Associations.

The above term has been used to indicate that, as the plants of the area are grouped into definite associations depending on environmental conditions, so the insects are grouped together according to their environment, of which, of course, the plant-covering is the most important factor. The insect-associations have been named more or less closely after the plant-associations, partly to avoid multiplication of names, and partly because the plant-covering is more conspicuous and forms the determining factor in the character of the insect-association. The range of species in an insect-association is, of course, not so clear-cut as in the plant-associations; for, while one may be able to say to a yard where tussock ends and swamp begins, the insects proper to one kind of environment may be found flying over the plants of another—as, for instance, when dragon-flies or sand-flies are found on the tussock. Again, insects that feed on the plants of one association may take shelter in another, as in the case of numerous moths which probably feed on the flowers of the shrub-land, but shelter by day in the forest, or may be attracted by night to a light on the tussock. The variety of plant-associations in close proximity to the station is a great advantage from most points of view, but in the present instance may lead to some errors in assigning certain insects to their proper associations.

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1. The Tussock Grass-land.

Large numbers of yellowish-white moths rise from the tussocks at every step. These are chiefly Crambus flexuosellus, but Scoparia salbulosella is almost equally common. Crambus simplex and C. ramosellus also occur. These all have a wing-span of about 23 mm., and the Scoparia has pale-grey front wings. The metallic-blue butterfly Chrysophanus boldenarum, of 22 mm. wing-span, flutters about the open spaces a few inches from the ground, and sinks from sight as it folds its wings over its back and displays only their mottled-grey undersides. The large attractive butterfly Argyrophenga antipodum flies lazily or sports merrily, usually in pairs, a few feet from the ground. This insect displays one of our best examples of protective coloration adapted to a special environment. The expanse of the wings is 45 mm., and their upper surfaces as well as the lower surfaces of the front pair have a rich brown background with bold orange masses, picked out with black and white spots. The remaining surfaces—namely, the lower ones of the back wings—have a buff background with longitudinal bright-silver stripes. The insect is most conspicuous while on the wing, but as soon as it settles on a tussock, its invariable resting-place, it becomes quite invisible: it exposes the buff and silver surfaces of its wings, which harmonize with the leaves of the tussock to an almost incredible degree of exactness. Occasionally Chrysophanus salustius, a yellow and black butterfly of 27 mm. wing-spread, may be seen flying low down, especially near the shrub-land, and a few moths of the night may be accidentally disturbed. The blow-flies will always be hovering round, and the eye will be caught by the furtive flights of several other Diptera, usually protectively coloured. The repulsive bristly Hystricia pachyprocta, with a stout yellow body 15 mm. in length, and the somewhat smaller Macquartia kumaraensis and M. subtilis, often remain stationary long enough to permit of observation; while the darting Limnia striata, 7 mm. long, and with curiously mottled wings, will usually require a grab with the hand to effect its capture. Two smaller flies that will hardly be noticed may be captured in scores by walking along with a net held near the surface of the tussock. One of these is probably an undescribed species of Trypeta, and the other may be a representative of a new genus of the family Dexiidae. Itamus varius, a predatory fly, 17 mm. in length, is very common.

Among the Hymenoptera the attractive Ichneumon solicitorius, with a yellow and black parti-coloured body, 15 mm. long, is frequently seen. Lissonota flavopicta, 10 mm. in length, with an ovipositor as long again, also occurs, as well as two other ichneumons that have not so far been identified. The common native bee, Dasycolletes hirticeps, with its bright-golden hairs on thorax and legs, is commonly seen working among the flowers of the introduced Hypochaeris radicata, and probably assists in the spread of this weed, which is the commonest introduced plant on the tussock-land. It may be noted here, for as far as it bears on insect-life, that this plant opens its flowers only from 8.30 a.m. till 8.30 p.m. even on the longest and most sunshiny days of the year. Another bee, 9 mm. in length, black but with downy white hairs on the thorax, also occurs on the tussock, but has not so far been identified. Specimens of the Coleoptera are not common. Down on the ground our handsome metallic black and green Trichosternus antarcticus, up to 30 mm. long, may be seen hurrying along, and dead specimens may be found in scores or hundreds lying on the gravel between the railway-lines. As this beetle is incapable of flight, it is difficult to see how it manages to climb over the rails, or how, once having

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got between them, it cannot get out again. Six specimens of a new and handsome species of Mecodema, bright shining black and 25 mm. in length, have also been taken crawling along among the tussocks, as well as a few specimens of the handsome Nascio enysi, 9 mm. long, black with four large yellow spots, and the less common Aemona separata, a large pale – yellowish – brown beetle, and the small black Anchomenus feredayi. On clayey banks among the tussock Cicindela feredayi, or a closely allied species, with an intricate yellow edging to its brownish – black elytra, darts in and out of its holes in the ground or takes short flights to elude capture.

The only Orthoptera noted are the common grasshopper, Phaulacridium marginale, which varies in colour from brown to green but always has a pair of white lines along the sides of the back of the thorax, and Paprides australis. Members of the other orders are not common. The cicada Melampsalta nervosa is more frequently heard than seen, and one of the Coccidae sometimes produces a striking appearance in the heart of the wild-spaniard (Aciphylla squarrosa). At first glance it appears as if a cup of flour had been emptied into the centre of the rosette of leaves, but on examination this is seen to be the waxy excretion of Pseudococcus oamaruensis, living specimens of which may be seen crawling among the mass of mealy powder. Anywhere near the swamps sand-flies are bound to occur, and an occasional dragon-fly may dart past.

Here also must be mentioned three introduced insects: the house-fly, which occurs sparingly indoors; the European earwig (Forficula auricularia), which is very common under boards, & c., lying round the railway-station buildings; and the sheep's nasal bot-fly (Oestrus ovis), which lays its eggs in the sheep's nostrils.

2. The Lake and Swamp.

In the shallow water near the edge of the lake the water-boatman (Anisops) occurs freely, darting up to the surface for air and down again to feed. In the same position the larvae and nymphs of most of the dragonflies may be found, but they are so effectively protected by their transparency or greenish tints that they easily escape observation despite their length of 20 mm. or over. In the swamp round the lake and lower down the Grassmere Stream the dragon-flies are the most conspicuous insects. The largest is Uropetala carovei, which is 8 cm. or 9 cm. in length and 10 cm. or 11 cm. in wing-span. As well as being the largest it is the rarest of the dragon-flies, perhaps because its larva and nymph, which is found in Lake Sarah up to 4.5 cm. long, must afford such suitable food for the large trout which abound there. This dragon-fly shows in perfection the habit of many of the species in frequenting a favourite spot over which it ranges in its hawking flights. Besides the swamps it is common on the rock-faces that border the Waimakariri. Next in size and frequency is Somatochlora smithii, 4.5 cm. in length and 6 cm. in wing-span. The thorax is metallic green, and in the male the proximal segments of the abdomen are of reduced diameter. This species dives into the water of smooth pools and picks off the surface floating larvae of certain gnats. It appears to wet only its head, and may make ten or twenty dives in a minute. Lestes colensonis, 4 cm. in length and with a very slender abdomen, is the commonest species, and the females seem to preponderate largely. Finally comes Xanthagrion zealandicum, 2.7 cm. in length, with an abdomen that is often reddish in the male and blue in the female.

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Of the Diptera by far the commonest is the gnat Chironomus, about 7 mm. long, which frequently occurs in such numbers that its swarms appear at a distance like columns of smoke. Various crane-flies are also common, the most noticeable being Tipula novarae, 25 mm. in length, and with a wing-span of 45 mm. T. obscuripennis and an unnamed species also occur. One particular moth, Xanthorhoe clarata, a handsome species with wavy lines of brown and yellow on the forewings, which are about 40 mm. across, has been captured only on the swamp-land, but its real home is probably in the adjacent shrubs.

3. The River-bed.

In the waters of the rapidly running streams are to be found the larvae of the sand-fly (Simulium australense) hanging to or crawling on the upper surface of the submerged stones, and there also occur underneath the stones larvae of the several Neuroptera to be mentioned immediately. These together with the sand-flies hover over the stony or shrubby banks of the river, or drift on to the tussock. The commonest species is Coloburiscus humeralis, with a wing-span of 30 mm., and three tails, the two outer of which are considerably longer than the body. Pseudoeconesus mimus occurs near streams in the forest. Pseudonema obsoleta, whose larva inhabits bored-out twigs in the forest-streams, is strongly attracted to light, and sometimes occurs in hundreds on the windows of the station. Its wing-expanse is about 35 mm. to 40 mm., and its antennae reach a length of 45 mm., being about three times as long as its body. Hydriobiosis umbripennis, whose larva is remarkable in that it does not live in any kind of case, occurs commonly. It has a wing-expanse of 25 mm., the front wings being sooty brown and the back ones transparent. Besides these there are one or perhaps two species of Ephemeridae that have not been so far identified, and the larva, but not the adult, of some species of Oniscigaster has been captured.

The river-bed is rich in other insects besides the Neuroptera. The moth Crambus xanthogrammus is very plentiful, flitting from stone to stone when disturbed. Its wings have a span of 25 mm., and the forewings are marked with broad wavy lines of black and white. I have not seen this moth elsewhere than on the river-bed, and regard it as very characteristic of this association. Several striking flies also occur, chiefly Anabarhynchus innotatus, with its bluish-grey body 14 mm. in length; Calcager apertum, of almost equal size; and the small Trypeta mentioned before as occurring on the tussock. At least one large but unidentified bee occurs on the river-bed, but nowhere else, so that, on the whole, this is a very distinct association, and a very numerous one considering the limited number of apparent food plants.

4. The Shrub-land.

The insects of this association are much fewer in number than would have been expected—unless, indeed, species more easily captured elsewhere in reality belong to the shrub. Among the beetles the green manuka-beetle (Pyronota festiva) is sometimes common, but remains unseen unless it is found away from its natural background. The rarer P. sobrina, with its bronze elytra, may also be found. Clay banks in the open spaces swarm with the active Cicindela tuberculata; and the yellow-spotted black ladybird, Vedalia cardinalis, occurs rarely. The same clay open spaces are frequented by great numbers of the hymenopterous Dasycolletes purpureus,

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and flitting among these may be seen the slender Gasteruption flavipes, a black wasp-like insect 10 mm. in length. A single specimen of stick-insect, probably an immature Clitarchus, has been found; and these, with an unidentified bug, comprise the total of the insects readily noted on the shrub-land. There are, however, some twenty moths that have been captured by night on the tussock or by day in the forest, and it is probable that the feeding-ground of these insects is the shrub-land, where nectar-producing plants are commonest.

5. The Forest.

Although twenty-four species of plants are recorded as growing in the forest, thirteen of these grow only along the stream-banks, and, of the remaining nine, one outnumbers all the others together by thousands to one. This plant is the Nothofagus cliffortioides, the mountain-beech. It is the only plant that reaches tree-size, the others forming merely a very scattered undergrowth, which in many places is quite absent. From this description it would be expected that the insect-life would be scanty. Moths, however, are very numerous, especially in individuals. As mentioned before, the noisy advance of an intruder will fill the air with hundreds of darting, fluttering specimens of Scoparia philerga, of 25 mm. wing-span. The front wings are mottled grey, and when closed have a conspicuous pale band across their basal third.

Hydriomena deltoidata, of 35 mm. wing-span, an attractive moth with brown front wings crossed by wavy bands of white, and Asaphodes megaspilata, a reddish-yellow moth of 23 mm. wing-span, are very plentiful in the clear spaces within the forest, while round its edge one disturbs thousands of specimens of Palaeomicra zonodoxa, a small yellow moth with fringed wings that glance like gold in the sun as the insect darts from shelter to shelter.

All these, however, are probably shrub-land insects hiding in the forest shades by day, for the patches of forest are so small that no part of them is far away from the surrounding shrub-lands.

The case-moth, Oeceticus omnivorus, however, belongs to the forest, as is shown by the beech-leaves woven in to conceal its leathery case.

Approaching the forest-streams one finds the river-bed insects becoming common, the sand-flies, caddis-flies, and Ephemeridae, with Pseudonema obsoleta specially numerous, as would be expected from the twig-boring habits of its larva. A single Dipteron, Mycetophila fagi, also occurs in large numbers.

6. The Rocks.

Large areas of bare rock occur at and above the 4,000 ft. line near the station, but none of these was visited except the small exposures on the Sugarloaf (4,475 ft.). Here the most conspicuous insect is a fat stone-grey grasshopper, up to 25 mm. in length. It is very distinct from all the species of which record has been found. The only other insect inhabiting these rocky spaces and not found on the tussock near by are three moths of about 25 mm. wing-span. Notoreas ferox has dark-brown almost black upper sides to its front wings, while the other wing surfaces are bright-orange with black wavy lines. Dasyuris anceps and an unidentifiable Harmologa are pale yellow on the wing-surfaces concealed when at rest, but stone-grey or brown on the surface exposed on alighting.

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C. List of Insects captured near the Station.

T = tussock; S = swamp; L = lake; R = river-bed; Sh = shrub-land; F = forest; R = rock ? means that owing to conditions of capture it is not certain that the insect really belongs to the association to which it is ascribed.

Order Hymenoptera.

  • Dasycolletes hirticeps. T.

  • D. purpureus. Sh.

  • Prosopis sp. T.

  • P. sp. R.

  • Ichneumon solicitorius. T.

  • I. spp. T.

  • Lissonota flavopicta. T.

  • Gasteruption flavipes. Sh.

Order Coleoptera.

  • Cicindela feredayi (?). T.

  • C. tuberculata. Sh.

  • Mecodema n. sp. T.

  • Trichosternus antarcticus. T.

  • Anchomenus feredayi. T.

  • Pyronota festiva. Sh.

  • P. sobrina. Sh.

  • Aemona separata. T.

  • Nascio enysi. T.

  • Vedalia cardinalis. Sh.

Order Lepidoptera.

  • Nyctemera annolata. T.

  • Orthosia comma. T. (?)

  • Physetica coerulea. T. (?)

  • Leucania propria. T. (?)

  • L. nullifera. T. (?)

  • L. acontistis. T. (?)

  • Melanchra compositis. T. (?)

  • M. insignis. T. (?)

  • Agrotis ypsilon. T. (?)

  • Hydriomena deltoidata. F. T. (?)

  • Venusia undosata. T. (?)

  • Asaphodes megaspilata. F. (?)

  • Xanthorhoe rosearia. T. (?)

  • X. clarata. S. (?)

  • Dasyurus anceps. R.

  • Notoreas ferox. R.

  • Sestra humeraria. T. (?)

  • Argyrophenga antipodum. T.

  • Chrysophanus salustius. T.

  • C. boldenarum. T.

  • Scoparia philerga. F.

  • S. salbulosella. T.

  • Platiptilia falcatilis. T.

  • Crambus flexuosellus. T.

  • C. simplex. T.

  • C. ramosellus. T.

  • C. xanthogrammus. R.

  • Harmologa sp. R.

  • Proteodes carnifex. T. (?)

  • Palaeomicra zonodoxa. F. (?)

  • Porina umbraculata. T. (?)

Order Diptera.

  • Mycetophilus fagi. F.

  • Chironomus zealandicus. S.

  • Tipula obscuripennis. S.

  • T. novarae. S.

  • T. sp. S.

  • Simulium australense. S.

  • Ryphus sp. T.

  • Anabarhynchus innotatus. R.

  • Itamus varius. T.

  • Limnia striata. T.

  • Trypeta sp. T. R.

  • Macquartia kumaraensis. T.

  • M. subtilis. T.

  • M. sp. R.

  • Hystricia pachyprocta. T.

  • Calcager apertum. T.

  • Species of fam. Dexiidae. T.

  • Calliphora quadrimaculata. T.

  • C. oceana. T.

  • Musca domestica. T.

  • Oestrus ovis. T.

Order Hemiptera.

  • Anisops wakefieldi. L.

  • Melampsalta nervosa. T. S.

  • Pseudococcus oamaruensis. T.

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Order Neuroptera.

  • Uropetala carovei. S.

  • Somatochlora smithii. S.

  • Lestes colensonis. S.

  • Xanthagrion zealandicum. S.

  • Coloburiscus humeralis. R.

  • Oniscigaster sp. R.

  • Pseudoeconesus mimus. R.

  • Pseudonema obsoleta. R. F.

  • Hydrobiosis umbripennis. R.

Order Orthoptera.

  • Clitarchus sp. S.

  • Phaulacridium marginale. T.

  • Paprides australis. T.

  • Species of Acridiidae. R.

  • Forficula auriculata. T.

Art. XII.—On a Partially White Form of Puffinus griseus Gmelin.

[Read before the Otago Institute, 12th June, 1917; received by Editors. 22nd December, 1917: issued separately, 24th May, 1918.]

Albinism of a complete or partial nature has several times been reported in connection with New Zealand birds, but the cases of its occurrence are not so frequent but that they should be recorded. On the 26th April, 1916, when returning from a trip to Stewart Island, I was shown by Mr. John Smith, of the Bluff, a live specimen of a mutton-bird (Puffinus griseus) which showed partial albinism. This interesting specimen was captured by Mr. Smith on Piko-mamaku-iti, the most northerly of the Titi Islands, where Mr. Smith was mutton-birding. The bird was a young one, and was caught in a nest. It was almost fully fledged. The head, neck, and upper part of the breast of this interesting specimen were pure white, back and upper part of the wings partly black, abdomen brown, the tail white. The bird, as mentioned above, was a young one, and in parts still had the down attached. Its beak was of a pinkish white, its legs pink, and its eye greenish. I examined the bird closely, and took certain measurements and other particulars, which were as follows:—

Inches.
Length from tip of beak to butt of tail 13.50
Length of side of beak 2.25
Length of beak from tip to nostrils 1.25
Length of wing from flexure 12.00
Total length of wing 19.00
Total spread of wings 42.50
Length of tarsus 2.25
Length of middle toe 2.75
Number of feathers in tail, fourteen.

Note.—The above measurements are, I believe, correct; but, as the bird was alive and resented handling, some difficulty was experienced in

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getting some of the measurements exactly. The normal colour of P. griseus is, of course, a sooty brown, the bill horn-colour, and the legs and feet brown. Mr. Smith informed me that partially white mutton-birds are not uncommon, but are yet sufficiently rare as to make a specimen of special interest even to the birders. I had hoped that this specimen would be sent to the Otago Museum, but I understand it has been disposed of privately.

As the normal number of feathers in the tail in Puffinus is only twelve, may not the above specimen be a hybrid between Puffinus griseus and some closely allied genus, such as Priocella, which has fourteen feathers in its tail? Of course, I may have made a mistake in identification, but the measurements closely accord with P. griseus. We know so little of the habits and life-histories of many of our sea-birds that some such explanation of these abnormal forms seems reasonable. The slight difference in the measurements with those laid down for P. griseus may be thus accounted for.

On the 14th June, 1916, I had an interview with Mrs. Sidney Ladbrook, of Mataura, who had just then returned from a birding expedition to Evening Island, off South Cape. She informed me that her party had found a pure-white mutton-bird on the island mentioned, but it was turned loose again. It seems that according to Maori superstition it is an evil omen to catch one of these rare specimens, portending death in the family of the captor. Mrs. Ladbrook informed me also that such a specimen is called a “jimmy bird” if it has white or pink eyes, but if the eyes are black it is known as a “queen bird” and the portent is less serious. The specimen which was caught on the trip just then completed was a pinkish white, but had black eyes. My informant says that these aberrant forms are sometimes found about the same spot in successive years. This latter statement receives corroboration from Mr. J. Bragg, of Half-moon Bay (see p. 38, Cockayne's Report on a Botanical Survey of Stewart Island, Parliamentary Paper C.–12, 1909: Government Printer).

Postscript.

Since the above article was written a curious coincidence has occurred which will probably serve to intensify the southern Maori superstition concerning the danger of interfering with a white mutton-bird. The bird referred to by Mrs. Ladbrook was, I understand, caught by her husband. During the birding season of 1917 Mr. and Mrs. Ladbrook went to the same island again, and during a storm two children—a daughter and a niece—whom they had taken with them were washed off the rocks and not seen again. Mrs. Ladbrook informed me that some fear of the result was expressed by the Maoris when the bird was caught. The belief is that the calamity will occur within a year, and in this instance has strangely proved quite accurate.

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Art. XIII.—Notes of a Botanical Visit to Hollyford Valley and Martin's Bay, with a List of Indigenous Plants.

[Read before the Otago Institute, 12th June, 1917; received by Editors, 22nd December, 1917: issued separately, 24th May, 1918.]

During the Christmas holidays of 1916–17 we, in company with some others, paid a visit to Martin's Bay, via the Hollyford Valley. We spent in all about ten days in the locality, examining the vegetation. Owing to lack of time and the difficult nature of the country, we were unable to climb any of the mountains, and consequently our notes relate only to the forest vegetation of Hollyford Valley and that of Martin's Bay itself. No list of the plants of these areas seems to have yet been published, so we append particulars of those seen by us, with some notes as to the ecological conditions and the forest vegetation.

Topography and Climate.

The Hollyford Valley from the point at which we entered it to the sea at Martin's Bay is about forty miles long. For over twenty miles of this distance it runs almost due north, and is bounded on the west by the Darran Range, which consists of very high and precipitous mountains, varying from 7,000 ft. to 9,000 ft. The principal peaks are Mount Christina (8,675 ft.) and Mount Tutoko (9,042 ft.). On the east side the mountains range from 4,000 ft. to 6,000 ft. in height. The valley is a narrow one, varying from less than a quarter of a mile to about two miles in width. The lower part trends more to the west, and consists of Lake McKerrow, twelve miles long, and a strip of three miles of level land to the sea. The mountains become much lower as the sea is approached. There is little doubt that this valley is subject to a very large rainfall, as is most of the western side of the South Island. The river is increased during its course by many snow-fed streams, which in the spring must be raging torrents. The Pyke River, which drains Lake Alabaster, is the largest of these streams, and is sufficiently deep to require horses to swim even when quite low, as it was at the time of our visit. We do not think this valley is subject to much frost in winter, and can vouch for the fact of great heat in summer. Our party did not experience a single shower during its visit, and from observations taken with the thermometer the shade temperature for several days exceeded 80° F. Where the track meets the valley below Howden Saddle the height above sea-level is between 500 ft. and 600 ft. The fall of the Hollyford River will therefore average about 15 ft. to the mile, although it is much greater in the upper part, as the last fifteen miles (including Lake McKerrow) is tidal.

Ecological Conditions.

The narrow valley, hemmed in by high mountains, and the high rainfall make the atmosphere warm and humid, and it consequently affords ideal conditions for plant-life. The soil mostly consists of detritus from the mountains, mixed with decaying vegetable matter, and is therefore rich and suitable for rank and rapid growth. The hanging mosses on all the tree-trunks and branches attest the high degree of atmospheric moisture.

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The hillsides are very steep, and give ample facilities for the growth of both sun- and shade-loving plants. The bush-line ascends to about 2,800 ft. or 3,000 ft. The trees throughout the valley are very high and have fairly close tops, but the high rainfall helps the formation of a stronger undergrowth than is usual in beech forests.

The Forest Association.

Round about Lake Howden the forest is almost entirely a Nothofagus one, but an immediate change is noticeable as soon as the descent to the Hollyford is commenced. The principal beech-trees are Nothofagus Menziesii and N. Solanderi, although N. fusca is found in patches and N. Blairii is also present. Gradually the forest changes as the valley is descended, until the taxads Dacrydium cupressinum, Podocarpus spicatus, and P. ferrugineus form a large part of the vegetation. P. Hallii and P. dacrydioides are also found, but do not appear to be anywhere very plentiful in the valley. The undergrowth consists of a second tier of smaller trees, the association being principally Pittosporum Colensoi, Nothopanax Edgerleyi, Carpodetus serratus, Metrosideros lucida (not abundant), Weinmannia racemosa (comparatively rare), and Griselinia littoralis, with a fair sprinkling of the fern-trees Hemitelia Smithii and Dicksonia fibrosa, and a considerable growth of Coprosma scrub and ferns. The islands in the river are usually covered with Coriaria ruscifolia, Cordyline australis, and Arundo conspicua, while Pratia angulata and Helichrysum bellidioides cover the open spaces.

Summary.

Perhaps the most interesting of our “finds” are Metrosideros florida Smith, and M. scandens Sol. Freycinetia Banksii A. Cunn. was common at both Martin's Bay and Lake Alabaster. Wahlenbergia congesta N. E. Brown was noted at Martin's Bay, which adds to the few known habitats of the species. The locality where found and relative abundance of the species are mentioned in the list. The total number of species noted was 226, belonging to 129 genera and 56 families.

List Of Indigenous Plants.

Pteridophyta.

Hymenophyllaceae.

  • Trichomanes reniforme Forst. f. Forest; not uncommon.

  • ——— venosum R. Br. Forest; rare.

  • Hymenophyllum sanguinolentum (Forst. f.) Sw. Tree-trunks.

  • ——— dilatatum (Forst. f.) Sw. Not very common.

  • ——— ferrugineum Colla. Fairly common.

  • ——— tunbridgense (L.) Sm. On tree-trunks.

  • ——— demissum (Forst. f.) Sw. Not uncommon.

  • ——— flabellatum Labill. Not plentiful.

Cyatheaceae.

  • Cyathea medullaris (Forst. f.) Sw. Martin's Bay; somewhat rare.

  • Hemitelia Smithii (Hook. f.) Hook Throughout

  • Alsophila Colensoi Hook. f. Not uncommon.

  • Dicksonia fibrosa Col. Not plentiful.

  • Leptolepia novae-zelandiae (Col.) Kuhn. Head of Hollyford Valley.

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Polypodiaceae.

  • Polystichum hispidum (Sw.) J. Sm. Throughout.

  • ——— vestitum (Forst. f.) Presl. Throughout.

  • Lindsaya viridis Col. Rare.

  • Asplenium adiantoides (L.) C. Chr. Near Mid Hut.

  • ——— bulbiferum Forst. f. Common throughout.

  • ——— flaccidum Forst. f. Common on trees.

  • Blechnum Patersoni (R. Br.) Mett. Fairly plentiful.

  • ——— discolor (Forst. f.) Keys. Dry open spaces.

  • ——— vulcanicum (Bl.) Kuhn. Epiphytic on rocky cliffs.

  • ——— lanceolatum (R. Br.) Sturm. Steep banks.

  • ——— penna marina (Poir.) Kuhn. Plentiful throughout.

  • ——— capense (L.) Schlecht. Abundant.

  • ——— fluviatile (R. Br.) Lowe. Not uncommon.

  • Hypolepis tenuifolia (Forst. f.) Bernh. Open spaces.

  • Adiantum affine Willd. Hidden falls, rocks.

  • Histiopteris incisa (Thbg.) J. Sm. Not abundant.

  • Pteridium esculentum (Forst. f.) Cockayne. Open places only.

  • Polypodium Billardieri (Willd.) C. Chr. Epiphytic on tree-trunks.

  • ——— gramitidis R. Br. Epiphytic on tree-trunks.

  • ——— diversifolium Willd. Climbing on tree-trunks.

  • Dryopteris pennigera Forst. f. Not uncommon.

  • Cyclophorus serpens (Forst f.) C Chr. Climbing on trees.

Gleicheniaceae.

  • Gleichenia dicarpa R. Br. Swampy places.

Osmundaceae.

  • Leptopteris hymenophylloides (A. Rich.) Presl. Fairly common.

  • ——— superba (Col.) Presl. Fairly abundant.

Ophioglossiaceae.

  • Botrychium ternatum Sw. Martin's Bay only.

Lycopodiaceae.

  • Lycopodium scariosum Forst. f. Not uncommon.

  • ——— volubile Forst. f. Fairly common.

  • ——— Billardieri Spring. Rare.

  • Tmesipteris tannensis Bernh. Not common; tree-trunks only.

Spermophyta.

Taxaceae.

  • Podocarpus Hallii T. Kirk. Not plentiful

  • ——— nivalis Hook. f. Only at high levels.

  • ——— ferrugineus Don. Common.

  • ——— spicatus R. Br. Plentiful

  • ——— dacrydioides A. Rich. Throughout.

  • Dacrydium cupressinum Sol. Fairly abundant throughout.

  • ———intermedium T. Kirk. Only near Martin's Bay.

  • ——— Colensoi Hook. Martin's Bay only.

  • Phyllocladus alpinus Hook. f. Not uncommon.

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Potamogetonaceae.

  • Potamogeton Cheesmanii A. Benn. In ponds, & c.

Scheuzeriaceae.

  • Triglochin striata Ruiz. & Pav. var. filifolia (Sieb.) Buchen. Wet places, Martin's Bay.

Gramineae.

  • Microlaena avenacea (Raoul) Hook. f. Common throughout.

  • Danthonia semiannularis R. Br. var. setifolia Hook. f. Rare; Hidden Falls.

  • ——— pilosa R. Br. Head of Lake McKerrow.

  • ——— Cunninghamii Hook. f. Not abundant.

  • Arundo conspicua Forst. f. Abundant on islands, & c.

  • Poa Colensoi Hook. f. Cliff-faces.

  • Fetuca littoralis Labill. Sand-dunes.

Pandanaceae.

  • Freycinetia Banksii A. Cunn. Abundant on creek-banks and at Martin's Bay and Lake Alabaster.

Cyperaceae.

  • Scirpus inundatus (R. Br.) Poir. Swampy places, Martin's Bay.

  • —— nodosus (R. Br.) Rottb. Brackish water.

  • —— frondosus Banks & Sol. Sand-dunes.

  • Carpha alpina R. Br. Dry heath, Martin's Bay.

  • Gahnia procera Forst. Damp places.

  • —— xanthocarpa Hook. f. (?). Martin's Bay only.

  • Uncinia uncinata (L. f.) Küken. Common in forest.

  • Carex ternaria Forst. f. Damp places.

  • —— lucida Boott. On bush tracks, damp ground.

  • —— pumila Thbg. Damp sand.

  • Leptocarpus simplex A. Rich. Salt marshes.

Juncaceae.

  • Juncus polyanthemos Buchen. Damp places.

Liliaceae.

  • Rhipogonum scandens Forst. Not abundant.

  • Enargea parviflora (Banks & Sol.) Hook. Fairly common.

  • Cordyline australis (Forst. f.) Hook. In Hollyford Valley.

  • —— indivisa Steud. Rare; near Howden Saddle.

  • Astelia nervosa Banks & Sol. Very abundant.

  • —— montana (T. Kirk) Cockayne. Dry places.

  • Dianella intermedia Endl. Lake McKerrow.

  • Phormium tenax Forst. River-bank.

  • —— Cookianum Le Jolis. Creek-banks, cliffs, & c.; common.

Iridaceae.

  • Libertia pulchella Spreng. Near Howden Saddle only.

  • —— ixioides Spreng. Dry places in forest.

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Orchidaceae.

  • Dendrobium Cunninghamii Lindl. Tolerably common.

  • Earina mucronata Lindl. Epiphytic on tree-trunks.

  • —— autumnalis (Forst. f.) Hook. Epiphytic; not common.

  • Pterostylis Banksii R. Br. In damp forest.

  • Thelymitra longifolia Forst. Martin's Bay.

  • Corysanthes macrantha Hook. f. Damp banks, & c.

  • —— oblonga Hook. f. Forest-floor.

  • Gastrodia Cunninghamii Hook. f. Beech forest.

  • Bulbophyllum pygmaeum Lindl. Rocks, Martin's Bay.

Chloranthaceae.

  • Ascarina lucida Hook. f. Fairly plentiful; Martin's Bay.

Monimiaceae.

  • Hedycarya arborea Forst. Hollyford Valley and Martin's Bay; common.

Fagaceae.

  • Nothofagus fusca (Hook. f.) Oerst. Common.

  • —— Menziesii (Hook. f.) Oerst. Common.

  • —— Solanderi (Hook. f.) Oerst. Common.

  • —— cliffortioides (Hook. f.) Oerst. At higher altitudes.

  • —— Blairii (T. Kirk) Diels. Not common.

Urticaceae

  • Urtica incisa Poir. Common in forest.

  • —— ferox Forst. Forest tracks; plentiful.

Loranthaceae.

  • Loranthus micranthus Hook. f. Martin's Bay

  • Elytranthe Colensoi (Hook. f.) Engl. Common on beech-trees.

  • —— tetrapetalus (Forst. f.) Engl. Common on Fagus; also found on Griselinia

  • —— flavida (Hook. f.) Engl. Comparatively rare.

Polygoniaceae.

  • Rumex neglectus Kirk. Martin's Bay.

  • —— flexuosus Sol. Martin's Bay.

  • Muehlenbeckia australis (A. Cunn.) Meissn. Not abundant.

  • —— complexa (A. Cunn.) Meissn. Fairly common.

  • —— axillaris Walp. Rare.

Caryophyllaceae.

  • Stellaria parviflora Banks & Sol. Open tracks, & c.

  • Colobanthus aciculais Hook. f. Rocks and dry places.

Ranunculaceae.

  • Clematis indivisa Willd. Rare.

  • Ranunculus hirtus Banks & Sol. Not uncommon.

  • —— rivularis Banks & Sol. Martin's Bay.

  • —— lappaceus Sm. Open spaces, Martin's Bay.

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Magnoliaceae.

  • Drimys colorata Raoul. Not common.

Cruciferae.

  • Cardamine heterophylla (Forst. f.) O. E. Schultz var. Forest tracks.

Saxifragaceae.

  • Carpodetus serratus Forst. Fairly plentiful.

Plttosporaceae.

  • Pittosporum Colensoi Hook. f. var. Scattered throughout.

Cunoniaceae.

  • Weinmannia racemosa L. f. Comparatively rare.

Rosaceae.

  • Rubus australis Forst. f. Throughout.

  • —— cissoides A. Cunn. Not plentiful.

  • —— subpauperatus Cockayne. Not uncommon.

  • Potentilla anserina (L.) var. anserinoides (Raoul) T. Kirk. Damp places.

  • Acaena novae-zelandiae Kirk. Throughout.

  • —— Sanguisorbae Vahl. Common.

  • —— microphylla Hook. f. On tracks, & c.

Geraniaceae.

  • Geranium microphyllum Hook. f. Near Martin's Bay.

  • —— sessiliflorum Cav. var. Sand-hills.

  • Oxalis magellanica Forst. Near Lake McKerrow.

Olacinaceae.

  • Pennantia corymbosa Forst. Not plentiful.

Euphorbiaceae.

  • Euphorbia glauca Forst. f. Sand-dunes only.

Coriariaceae.

  • Coriaria ruscifolia L. var. Abundant and of great size.

  • —— thymifolia Humb. & Bonp. var. Fairly plentiful.

  • —— angustissima Hook. f. Not common.

Leguminosae.

  • Sophora tetraptera J. Mull. var. Lake McKerrow and Martin's Bay.

  • Carmichaelia flagelliformis Col. (?). Martin's Bay.

Elaeocarpaceae.

  • Aristotelia racemosa (A. Cunn.) Hook. f. Not abundant.

  • —— Colensoi Hook. f. Rare.

  • —— fruticosa Hook. f. Common.

  • Elaeocarpus Hookerianus Raoul. Comparatively rare.

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Malvaceae.

  • Hoheria populnea A. Cunn. var. Pyke River.

  • Gaya Lyallii Baker. River-valleys.

Violaceae.

  • Viola Cunninghamii Hook. f. Not uncommon.

  • —— filicaulis Hook. f. Head of Hollyford Valley; rare.

  • —— —— var. hydrocotyloides (J. B. Armstg.) T. Kirk. Damp tracks.

  • Melicytus ramiflorus Forst. Common throughout.

Thymelaeaceae.

  • Pimelea Lyallii Hook. f. Sand-hills, Martin's Bay.

Myrtaceae.

  • Leptospermum scoparium Forst. Martin's Bay; not plentiful.

  • Metrosideros lucida Forst. f. Growing throughout, but local.

  • —— hypericifolia A. Cunn. Lower Hollyford.

  • —— florida Sm. Martin's Bay.

  • —— scandens Sol. Forest, Martin's Bay.

  • Myrtus pedunculata Hook. f. Common.

Onagraceae.

  • Epilobium rotundifolium A. Rich. Bush tracks.

  • —— linnaeoides Hook. f. Open spaces.

  • —— melanocaulon Hook. f. Creek-beds.

  • —— nummularifolium A. Cunn. var. minimum T. Kirk. Forest.

  • Fuchsia excorticata L. f. Not uncommon.

  • —— Colensoi Hook. f. Rare.

Halorrhagaceae.

  • Halorrhagis erecta (Murr.) Schindler. Sand-hills.

  • Gunnera albocarpa (T. Kirk) Cockayne. Damp places.

Araliaceae.

  • Nothopanax simplex (Forst.) Seem. Throughout.

  • —— Edgerleyi (Hook. f.) Seem. Throughout.

  • —— Colensoi (Hook. f.) Not plentiful.

  • —— linearis (Hook. f.) Harms. Near Howden Pass.

  • Pseudopanax crassifolium (Sol.) C. Koch var. unifoliatum T. Kirk. Not common.

  • Schefflera digitata Forst. Damp situations; fairly common.

Umbelliferae.

  • Hydrocotyle novae-zealandiae DC. Damp places.

  • Apium prostratum Labill. Near sand-hills.

  • —— filiforme (A. Rich.) Hook. Not uncommon.

  • Anisotome intermedia Hook. f. Rocks and creek-banks, Martin's Bay.

Cornaceae.

  • Griselinia littoralis Raoul. Not uncommon.

  • —— lucida Forst. Martin's Bay; not uncommon.

Ericaceae.

  • Gaultheria antipoda Forst. f. var. erecta Cheesem. Near Martin's Bay.

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Epacridaceae.

  • Styphelia acerosa Sol. Martin's Bay and Howden Saddle.

  • —— Fraseri (A. Cunn.) F. Muell. Martin's Bay.

  • Archeria Traversii Hook. f. Rare.

  • Dracophyllum longifolium (Forst. f.) R. Br. Not plentiful.

Myrsinaceae.

  • Suttonia divaricata (A. Cunn.) Hook. f. Throughout.

  • Rapanea Urvillei (A. DC.) Mez. Rare.

Convolvulaceae.

  • Calystegia tuguriorum (Forst. f.) R. Br. Rear of sand-hills.

  • —— sepium R. Br. (?). Near sand-hills.

  • —— Soldanella R. Br. On sand, Martin's Bay.

Boraginaceae.

  • Myosotis Lyallii Hook. f. (?). Bush tracks.

Labiatae.

  • Mentha Cunninghamii Benth. Bush tracks.

Scrophularinaceae.

  • Veronica salicifolia Forst. Common; creek-banks.

  • —— subalpina Cockayne. Creek-banks.

  • —— leiophylla Cheesem. (?). Hidden Falls; not common.

  • —— Lyallii Hook. f. Not uncommon.

  • —— catarractae Forst. Hidden Falls.

  • —— buxifolia Benth. Rare.

  • Ourisia caespitosa Hook. f. Near Howden Saddle.

Rubiaceae.

  • Coprosma lucida. Forst. Common throughout.

  • —— parviflora Hook. f. Fairly plentiful.

  • —— acerosa A. Cunn. var. arenaria T. Kirk. Dunes.

  • —— foetidissima Forst. Common in forest.

  • —— rotundifolia A. Cunn. In forest.

  • —— areolata Cheesem. In forest.

  • Nertera dichondraefolia (A. Cunn.) Hook. Common.

  • —— depressa Banks & Sol. Comparatively rare.

Campanulaceae.

  • Pratia angulata (Forst. f.) Hook. f. Common.

  • —— —— variety with small leaf. In forest.

  • Wahlenbergia albomarginata Hook. Open spaces.

  • —— congesta (Cheesem.) N. E. Brown. Sand-hills, Martin's Bay.

  • Lobelia anceps L. Wet places, Martin's Bay.

Compositae.

  • Lagenophora pumila (Forst. f.) Cheesem. Not uncommon; Martin's Bay.

  • —— petiolata Hook. f. Plentiful.

  • Olearia arborescens (Forst. f.) Cockayne and Laing. Creek-banks.

  • —— ilicifolia Hook. f. Plentiful.

  • —— avicenniaefolia Hook. f. Common in places.

  • Celmisia longifolia Cass. var. Not plentiful.

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  • Brachycome Sinclairii Hook. f. On tracks, & c.

  • Raoulia glabra Hook. f. Dry places.

  • —— australis Hook. f. Shingle-beds.

  • Gnaphalium luteo-album L. Not uncommon.

  • —— Lyallii Hook. f. Rocks, Martin's Bay.

  • Helichrysum bellidioides (Forst. f.) Willd. Not plentiful.

  • Craspedia uniflora Forst. f. var. robusta Hook. f. Common; Martin's Bay.

  • Cotula dioica Hook. f. Open places; common.

  • Senecio elaeagnifolius Hook. f. Not plentiful.

Art. XIV.—Notes of a Botanical Excursion to Bunkers Island (Stewart Island).

[Read before the Otago Institute, 12th June, 1917; received by Editors, 22nd December, 1917; issued separately, 24th May, 1918.]

On the 7th April, 1917, in company with Mr. G. Biggar, of Croydon, I paid a visit to Bunkers, one of the group of islands off the north-east coast of Stewart Island. This scrap of land lies to the eastward of Herekopere, and is one of the Fancy Group. It is only about 700 metres long, with an average width of less than 100 metres. The highest point above sea-level is about 35 metres. The eastern end is a separate island at high tide, and in another part the island is almost cut in two by the action of the sea. The geological formation consists of rotten granite, a good deal of it being simply a sort of gritty clay. The sea has eaten into this soft material on the southern side, with the result that there are several slips and cliffs there, all of which show much recent denudation. Mr. C. Hansen, of Half-moon Bay, informs me that there is comparatively shallow water on the south and south-west of the island, which suggests that at no distant date the island was larger than at present.

Ecological Conditions.

In common with all other islands of the Stewart Group, Bunkers is subject to a high rainfall, with high winds, but a comparatively mild and equable temperature. On this island there is only a thin coating of peat. Probably it is on this account that there is but little evidence of bird traffic so far as the burrowing petrels are concerned, although penguins were not uncommon The edaphic conditions and the exposed situation combine to prevent any extent of forest vegetation, although there are not wanting signs of a onetime forest formation. Probably when the island was larger such a formation existed, but the present plant-covering might be called a “scrub” association.

Plant-Formations.

These may be divided under the heads of “scrub” and “rocks and cliffs,” but with a view to saving space I do not intend to do more than outline the associations.

The physiognomy of the scrub shows a smooth exterior, and has the usual grey-green colour of the Olearia-Senecio association of the Stewart Botanical District. Olearia angustifolia is the commonest plant near the sea, but Senecio rotundifolia and Veronica elliptica are common. Curious to relate, Olearia Colensoi, so common in similar associations on the islands in the vicinity, appears to be absent. Here and there Stilbocarpa Lyallii is seen in patches, and also the common coastal ferns Asplenium lucidum and

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A. obtusatum. Here and there are open patches covered with Hierochloe redolens mixed with Pteridium esculentum and Histiopteris incisa, and in other places with Arundo conspicua. On the higher portion of the island the principal “shrub” is Olearia arborescens, which grows to the dimensions of a small tree with a thick trunk and much-branched top. Great patches of Polypodium diversifolium are common under the scrub. The rock and cliff vegetation consists of the usual Poa Astom, Crassula moschata, Myosotis albida, Cyclophorus serpens, Tetragoma trigyna, and Apium prostratum. I do not propose to further describe in detail the plant-associations, but am appending a list of the plants noted, from which it will be seen that a somewhat varied type of plant finds a home on this isolated piece of soil.

Conclusion.

The list of species shows certain surprises. I saw no sign of Olearia Colensoi, so common on many other islands in this locality. Poa foliosa and Senecio Stewartiae, so plentiful on Herekopere, only about a mile distant, were also absent. On the other hand, the presence of Melicytus lanceolatus, Hemitelia Smithi, Weinmannia racemosa, and the orchids Earina mucronata and E. autumnalis suggest a former forest vegetation, of the destruction of part of which by fire there was some evidence. The total number of species listed is seventy, belonging to fifty-three genera and twenty-eight families. In addition to these, five introduced species were noted.

List of Plants Noted.

Pteridophyta.

Cyatheaceae.

  • Hemitelia Smithn (Hook. f.) Hook.

  • Alsophila Colensoi Hook f.

Polypodiaceae.

  • Polystichum vestitum (Forst. f.) Presl.

  • Asplenium obtusatum Forst, f.

  • —— scleroprium Homb. & Jacq.

  • —— lucidum Forst. f.

  • —— flaccidum Forst. f.

  • Blechnum capense (L.) Schlecht.

  • Histiopteris incisa (Thbg.) J. Sm.

  • Pteridium esculentum (Forst. f.) Cockayne.

  • Polypodium diversifolium Willd.

  • Cyclophorus serpens (Forst. f.) C. Chr.

Lycopodiaceae.

  • Lycopodium fastigitum R. Br.

  • —— volubile Forst. f.

  • —— Billardieri Spring.

Spermophyta.

Gramineae.

  • Hierochloe redolens (Forst. f.) R. Br.

  • Arundo conspicua Forst. f.

  • Poa Astoni Petrie.

  • —— caespitosa Forst. f.

  • —— imbecilla Forst. f.

– 156 –

Cyperaceae.

  • Scirpus nodosus (R. Br.) Rottb.

  • Uncinia pedicellata Küken. (?).

Juncaceae.

  • Luzula campestris DC.

Liliaceae.

  • Astelia nervosa Banks & Sol.

  • Phormium Cookianum Le Jolis.

Orchidaceae.

  • Earina mucronata Lindl.

  • —— autumnalis (Forst. f.) Hook.

  • Thelymitra longifolia Forst.

  • Prasophyllum Colensoi Hook. f.

Polygonaceae.

  • Muehlenbeckia australis (Hook. f.) Meissn.

Aizoaceae.

  • Tetragonia trigyna Banks & Sol.

Cruciferae.

  • Cardamine heterophylla (Forst. f.) O. E. Schultz var.

Crassulaceae.

  • Crassula moschata Forst. f.

Cunoniaceae.

  • Weinmannia racemosa L. f.

Rosaceae.

  • Acaena Sanguisorbae Vahl. var. pusilla Bitter.

Geraniaceae.

  • Geranium microphyllum Hook. f.

Violaceae.

  • Melicytus lanceolatus Hook. f.

Thymelaeaceae.

  • Pimelea Lyallii Hook. f.

Onagraceae.

    • Epilobium pubens A. Rich.

    Halorrhagaceae.

    • Halorrhagis erecta (Murr.) Schindler.

    • Ghnnera albocarpa (T. Kirk) Cockayne.

    Araliaceae.

    • Stilbocarpa Lyallii J. B. Armstrong.

    • Nothopanax Colensoi (Hook. f.) Seem.

    – 157 –

    Umbelliferae.

    • Hydrocotyle novae-zealandiae DC.

    • Apium prostratum Labill.

    Cornaceae.

    • Griselinia littoralis Raoul.

    Myrsinaceae.

    • Rapanea Urvillei (A. DC.) Mez.

    Convolvulaceae.

    • Calystegia tuguriorum (Forst. f.) R. Br.

    Boraginaceae.

    • Myosotis albida (T. Kirk) Cheesem.

    Scrophularinaceae.

    • Veronica elliptica Forst. f.

    Rubiaceae.

    • Coprosma lucida Forst. f.

    • —— areolata Cheesem.

    • —— foetidissima Forst.

    • —— acerosa A. Cunn.

    • —— parviflora Hook. f.

    • Nertera dichondraefolia (A. Cunn.) Hook. f.

    • —— depressa Banks & Sol.

    Campanulaceae.

    • Wahlenbergia gracilis (Forst. f.) A. DC.

    Compositae.

    • Lagenophora pumila (Forst. f.) Cheesem.

    • Brachycome Thomsoni T. Kirk.

    • Olearia angustifolia Hook. f.

    • —— arborescens (Forst. f.) Cockayne and Laing.

    • Gnaphalium luteo-album L.

    • —— collinum Labill.

    • Helichrysum bellidioides (Forst. f.) Willd.

    • —— filicaule Hook. f.

    • Senecio lautus Forst. f.

    • —— rotundifolius Hook. f.

    • Sonchus littoralis (Kirk) Cockayne.

    Introduced Plants.

    • Holcus lanatus L.

    • Poa trivialis Lind. (?).

    • Stellaria media Vill.

    • Brassica oleracea L.

    • Hypochaeris radicata L.

    – 158 –

    Art. XV.—Notes on a Botanical Visit to Coll or Bench Island (Stewart Island).

    [Read before the Otago Institute, 12th June, 1917; received by Editors, 22nd December, 1917; issued separately, 24th May, 1918.]

    On the 10th April, 1917, in company with Mr. G. Biggar, of Croydon, I had the opportunity, by courtesy of Mr. Henry Hansen, of Half-moon Bay, of spending a few hours on the above island—one of those off the north-east coast of Stewart Island, distant about six miles from the mainland, at Half-moon Bay. The whole surface of the island is clad with a close forest and scrub association, which in parts is difficult to get through, and consequently my list can hardly be considered exhaustive, but it gives a good idea of the plant-covering. The general characteristics of the coastal scrub of all these outlying islands are very similar. This island, however, contains a forest association something like Pukeokaoka,* differing considerably from both Herekopere and Bunkers, which are its nearest neighbours. The top of the island is somewhat broken by a series of undulations, and the chief features of the vegetation are the close coastal scrub, the great quantities of Stilbocarpa Lyallii, and the large groves of Dicksonia squarrosa. The ferns of the forest-floor are of immense size, the fronds of Asplenium bulbiferum and A. falcatum attaining a height of 1.5 metres. Petrels and other burrowing-birds do not seem very plentiful except towards the southern end of the island, but penguins (Megadyptes antipodium) were common at the time of our visit, and appeared to be moulting. The influence of these birds on the vegetation must be considerable, both on account of their traffic and by the enrichment of the ground by their droppings.

    I do not intend further describing the plant-associations in detail, but append a list of species noted. From this it will be seen that these number fifty-four, belonging to thirty-seven genera and twenty-four families. For the first time, I think, Senecio Stewartiae is definitely reported from this island. It is plentiful at the south end, but was not seen elsewhere.

    List of Plants Noted.

    Pteridophyta.

    Hymenophyllaceae.

    • Hymenophyllum sanguinolentum (Forst. f.) Sw.

    • —— dilatatum (Forst. f.) Sw.

    • —— demissum (Forst. f.) Sw.

    • —— tunbridgense (L.) Sm.

    Cyatheaceae.

    • Dicksonia squarrosa (Forst. f.) Sw.

    Polypodiaceae.

    • Polystichum vestitum (Forst.) Presl.

    • —— hispidum (Sw.) Sm.

    [Footnote] * See D. L. Poppelwell, Notes on the Plant-covering of Pukeokaoka, Stewart Island, Trans. N.Z. Inst., vol. 48, p. 244, 1916.

    [Footnote] † See D. L. Poppelwell, Notes of a Botanical Visit to Herekopere Island, Stewart Island, Trans. N.Z. Inst., vol. 47, p. 142, 1915.

    [Footnote] ‡ See article in this volume, p. 154

    – 159 –
    • Asplenium obtusatum Forst. f.

    • —— scleroprium Homb. & Jacq.

    • —— lucidum Forst. f.

    • —— bulbiferum Forst. f.

    • —— flaccidum Forst. f.

    • —— falcatum Lam.

    • Blechnum durum (Moore) C. Chr.

    • —— penna marina (Poir.) Kuhn.

    • Histiopteris incisa (Thbg.) J. Sm.

    • Pteridum esculentum (Forst. f.) Cockayne.

    • Polypodium Billardieri (Willd.) C. Chr.

    • —— grammitidis R. Br.

    • —— diversifolium Willd.

    Lycopodiaceae.

    • Tmesipteris tannensis Bernh.

    Spermophyta

    Taxaceae.

    • Podocarpus ferrugineus Don

    Gramineae.

    • Hierochloe redolens (Forst. f) R. Br.

    • Poa Astoni Petrie.

    Cyperaceae.

    • Scirpus aucklandicus (Hook. f.) Boeck.

    • —— nodosus (R. Br.) Rottb.

    • Carex trifida Cav.

    • —— lucida Boott.

    Liliaceae.

    • Rhipogonum scandens Forst.

    Orchidaceae.

    • Earina mucronata Lindl

    Polygoniaceae.

    • Muehlenbeckia australis (Forst. f.) Meissn.

    Aizoaceae.

    • Tetragonia trigyna Banks & Sol.

    Crassulaceae.

    • Crassula moschata Forst. f.

    Pittosporaceae.

    • Pittosporum Colensoi Hook. f. var.

    Cunoniaceae.

    • Weinmannia racemosa L. f.

    Rosaceae.

    • Rubus australis Forst. f.

    Violaceae.

    • Melicytus lanceolatus Hook. f.

    Myrtaceae.

    • Metrosideros lucida (Forst. f.) A. Rich.

    Araliaceae.

    • Stilbocarpa Lyallii J. B. Armstrong.

    • Nothopanax Edgerleyi (Hook. f.) Seem

    • Pseudopanax crassifolium (Sol.) C. Koch var. unifoliatum T. Kirk.

    Umbelliferae.

    • Hydrocotyle novae-zealandiae DC.

    • Apium prostratum Labill

    Cornaceae.

    • Griselinia littoralis Raoul.

    Myrsinaceae

    • Rapanea Urvellei (A. DC.) Mez.

    Scrophularinaceae.

    • Veronica elliptica Forst f.

    Rubiaceae.

    • Coprosma rotundifolia A. Cunn.

    • —— areolata Cheesem

    • —— foetidissima Forst

    • Nertera dichondraefolia (A. Cunn.) Hook f.

    Compositae.

    • Olearia angustifolia Hook. f.

    • Erechtites scaberula Hook. f.

    • Senecio Stewartiae J. B. Armstrong.

    • —— rotundifolius Hook f.

    – 160 –

    Art. XVI.—On the Age of the Alpine Chain of Western Otago.

    [Read before the Otago Institute. 9th October, 1917; received by Editors, 22nd December, 1917; issued separately, 24th May, 1918.]

    Plate VIII.

    The alpine chain of Western Otago consists of folded altered rocks of older Palaeozoic age. Deeply involved in the eastern folds of this chain there occurs a remarkable wedge of Camozoic marine strata that can be traced as a narrow band from Bob's Cove, on the north shore of the middle arm of Lake Wakatipu, across the Richardson Mountains to the sources of the Shotover River, a distance of over twenty-five miles. The trend of this band is north-north-east, and its limits in that direction have not yet been defined. As exposed in the deep gorges with which the mountains are scored, the visible involvement exceeds 4,500 ft. At its southern end the thickness of the infolded beds is about 80 ft., and in the Shotover Mountains 12 ft.

    At Bob's Cove, where these beds cover an area about half a square mile in extent, the succession is: Breccia-conglomerate (bottom); sandy clay; limestone; sandstone, in places pebbly.

    Fossil mollusca are fairly abundant, but usually badly preserved. The few forms collected by me during my survey* of the Queenstown district in 1908–9 indicated an Oamaruian (Miocene) age, but the absence of certain molluscs that are held to be characteristic of that period left the matter of their age in some doubt; and in view of the profound involvement of these beds and the bearing this involvement has on the date of the tectonic movement that culminated in the building of the alpine chain I revisited Bob's Cove last January, and on that occasion collected from the sandstone lying below the limestone good examples of the following:—

    Pecten huttoni Park.
    Cucullaea alta Sowerby.
    Limopsis zitteli Iher.
    Cardium huttoni Iher.
    Venericardia purpurata (Desh.).
    Ostrea wüllerstorfi Zittel.
    Polinices ovatus (Hutton).
    Ancilla hebera Hutton.
    Dentalium mantelli Zittel.

    Of these, Pecten huttoni, Cucullaea alta, Limopsis zitteli, Cardium huttoni, Ostrea wüllerstorfi, and Dentalium mantelli are, so far as at present known, confined to the Oamaruian, and their presence may be regarded as satisfactory evidence that the Bob's Cove beds belong to the higher portion of that system, and the mountain-building movement which led to the deep involvement of these beds took place in post-Miocene times, probably in the early Pliocene.

    [Footnote] * James Park, The Geology of the Queenstown Subdivision, Bull. No. 7 (n.s.), N.Z. Geol. Surv., p. 66, 1909.

    [Footnote] † Loc. cit., pp. 60–66.

    Picture icon

    Plate VIII.
    Bob's Cove, Lake Wakatapu, showing warping of the Tertiary beds A, Bob's Cove limestone, B, fossils.

    – 161 –

    Art. XVII.—Notes on New Zealand Floristic Botany, including Descriptions of New-Species, & c. (No. 3).

    [Read before the Wellington Philosophical Society, 24th October, 1917; received by Editors, 31st December, 1917; issued separately, 30th May, 1918.]

    Plates IX, X.

    I. Introduction.

    In this series of papers, two of which have already appeared,* I am carrying out, as far as lies in my power, the views regarding species and taxonomic procedure expressed in my paper entitled “A Consideration of the Terms ‘Species’ and ‘Variety’ as used in Botany, with Special Reference to the Flora of New Zealand.” These views are by no means of my own formulating. On the contrary, they represent what I believe to be the consensus of opinion of those engaged in the only true way of studying specific distinctness—i.e., by means of experiments in genetics according to present-day methods. If my views possess any originality it lies in the method of stating the case and in the proposals suggested for meeting the practical difficulty of making a flora serve its primary purpose of enabling any plant to be readily recognized and accorded its proper name. As the length of the paper cited above and the method of presentation of its arguments may serve to somewhat becloud the practical application of the theories advocated therein, I now briefly state the principles which in this series of papers are the guide for the establishing of species or varieties:—

    (1.)

    The starting-point in the setting-up of species is the individual.

    (2.)

    Groups of individuals which resemble one another in every character and reproduce their like, subject, of course, to unfixed fluctuating variations, constitute specific units and may be designated “microspecies.”

    (3.)

    One microspecies, if all its related microspecies have been obliterated or have never existed, constitutes an invariable or fixed systematic species. Examples: Agathis australis, Veronica cupressoides, Epilobium pallidiflorum.§

    (4.)

    Two or more closely related microspecies may be united into a group for the sake of: (a) convenience in identification, (b) emphasizing the close relationship of minor groups (microspecies), (c) phytogeography.

    (5.)

    Such a major group as constituted in (4) forms an aggregate or collective species.

    (6.)

    Aggregate species are the “variable species” of floras. Examples: Poa anceps, Ranunculus lappaceus, Pimelea prostrata.

    (7.)

    An aggregate species has obviously no real existence; it is a convenient abstraction only.

    [Footnote] * Trans. N.Z. Inst., vol. 48, pp. 193–202, 1916; and ibid., vol. 49, pp. 56–65, 1917.

    [Footnote] † Trans. N.Z. Inst., vol. 49, pp. 66–79.

    [Footnote] ‡ Other names given to such groups are “biotypes,” “petites espéces,” and “elementary species.”

    [Footnote] § It might well be argued that there are no species which consist of only one microspecies, and that intense study and experiment will demonstrate their polymorphy.

    – 162 –
    (8.)

    Each microspecies of the combination forming an aggregate species should theoretically receive a varietal name.

    (9.)

    But in practice the procedure advocated in (8) would defeat its purpose if the microspecies were too much alike, so in this case groups of virtually identical microspecies can receive varietal rank.

    (10.)

    It follows then that, similarly with species, varieties are of two kinds, one reproducing itself true and the other an aggregate.

    (11.)

    Aggregate varieties, though abstractions only, so far as the eye goes approximate to true entities.

    (12.)

    The description of an aggregate species applies to no special individual, but includes the striking characters common to all its varieties; obviously, then, there is no “type.”

    (13.)

    If the opinions as given above are accepted, a trinomial nomenclature becomes necessary, the first name being that of the genus, the second that of the species, and the third that of the variety.

    (14.)

    If the opinion is held that every microspecies has been at one time related closely to other microspecies, it follows that even the invariable species mentioned in (3) should be given varietal names. But this procedure seems unnecessary, and perhaps mischievous, since a binomial for such species is convenient and it indicates that the specific group stands apart from all others.*

    (15.)

    In certain cases groups, otherwise well defined, seem to be united by “intermediates” which cannot be joined to such groups or made into one or more species. Such “intermediates,” according to the teachings of genetics, may be assumed to be hybrids between microspecies, and their occurrence should not forbid the separation into species or varieties, as the case may be, of the distinct true-breeding groups (microspecies) which are connected by such presumably hybrid intermediates.

    As a botanical ecologist, endeavouring to define and classify the plant-communities of New Zealand and to learn something about the physiological requirements of the species and the physiology of form, I have keenly felt, for many years, the want of names for many well-marked groups of individuals which, though fitting fairly well into one or other of the recognized aggregate species, differ so greatly in their ecological requirements from other members of the species to which they are referred that to call them by the same name is most misleading, and in no few instances will cause incorrect ecological deductions.

    [Footnote] * Of course, as at present accepted, there are many different degrees of specific isolation, but it should be possible to gradually bring about greater uniformity in this regard.

    [Footnote] † This has frequently been done in the New Zealand flora, but not because of any special biological explanation such as that of microspecific hybrids. Celmisia discolor and C. incana (Manual, pp. 304–5), Gnaphalium Lyallii and G. trinerve (Manual, p. 323), and many species of Veronica are cases in point. On the other hand, distinct microspecies are denied specific rank owing to their being connected by “intermediates.” Examples are: Epliobium pedunculare reduced to a var. of E. nummularifolium (Manual, p. 180), the treatment of the groups included under Hoheria populnea (Manual, p. 79), and the retention of vars. robusta, minor, and lanata as varieties of Craspedia uniflora (Manual, p. 348).

    [Footnote] ‡ Of what value would be an account of the leaf-anatomy or the rate of transpiration in the leaves of certain individuals of Pittosporum tenuifolium, Acaena Sanguisorbae, Aristotelia fruticosa, Geranium sessiliflorum, Celmisia coriacea, and Myosotis antarctica under the above specific names, unless a description of the actual plants dealt with were given—i.e., unless they were accorded for the time being the status of microspecies?

    – 163 –

    It may well be argued that the trend of botanical taxonomy the world over is to bestow specific names on the varieties, thus breaking up the long-recognized aggregates into so-called “valid species.” Certainly such groups distinguished by binomials are convenient for the ecologist working at synecology, but they are of far less use to the autecologist, the floristic phytogeographer, or the student of evolution or genetics than are aggregates with their varieties distinguished by trinomials. Once cease to emphasize the genetic aspect of taxonomy, away goes its philosophy—indeed, it ceases to be a science!

    To apply the principles enumerated above is far from easy; they probably represent ideals impossible of full attainment. Research is demanded in many directions; above all, living material is essential—field observations as accurate as possible must be made, and experiments in the garden must finally decide those doubtful points impossible to be solved either in the field or the herbarium.

    With regard to the species, & c., dealt with in the present paper I have received valuable assistance from various sources without which the work could not have been carried on. I must especially thank Mr. H. H. Allan, M.A., F.L.S. (Ashburton); Mr. B. C. Aston, F.I.C. (Wellington); Mr. H. Carse (Kaiaka); Mr. C. E. Christensen (Hanmer); Miss E. M. Herriott, M.A. (Christchurch); the Rev. J. E. Holloway, D.Sc. (Hokitika); Mr. R. M. Lamg, M.A., B.Sc. (Christchurch); Messrs. Nairn and Son (Christ-church); Mr. D. Petrie, M.A. (Auckland); Mr. R. H. Rockel, M.A. (New Plymouth); Professor A. Wall, M.A. (Christchurch); and Mr. J. Young (Christchurch) — all of whom have given me much-valued aid both in material and information. I must also acknowledge the kindness of Professor H. B. Kirk, M.A. (Wellington), who has afforded me every facility for using the herbarium of the late Mr. T. Kirk, F.L.S.; of Dr. J. A. Thomson for similar privileges with regard to Colenso's herbarium in the Dominion Museum; and of Mr. A. Turnbull, F.L.S., who has allowed me to consult his splendid library of Australasian and Pacific literature.

    As far as possible I have deposited in the herbarium of the Canterbury Museum, Christchurch, type specimens of all the species, & c., dealt with in this series of papers.

    II. Taxonomic.

    25.* Carmichaelia Fieldii Cockayne sp. nov.

    Frutex parvus, glaber, afoliatus nisi juventute, prostratus. Rami usque ad 40 cm. longi sed saepe multo breviores, 2 mm. lati, arcuati, compressi, striati, pauciramosi, cortice luteo-viride obtecti. Racemi brevissimi, nunquam fasciculati, 2–5 flori; pedicelli ± 3 mm. longi, glabri. Flores. non visi. Legumen 3–4 mm. longum, oblique-ovoideum vel-oblongum, quam maxime turgidum, subrugosum, nigrum; rostrum basi crassum, curvatum, apiculatum. Semina 2–5 (plerumque 3–4), pallide brunnea.

    South Island: North-western Botanical District—Growing as a small colony on a wind-swept sandstone ledge on a small island rising, at low water, out of the mud-flat of Westhaven (West Wanganui). W. H. Field and B. C. Aston!

    The above description is drawn up from insufficient material. In many cases the capsules were much damaged.

    Carmichaelia Fieldii appears to come nearest in affinity to C. juncea Col., but it differs in its prostrate habit, broader always more or less

    [Footnote] * The numbers follow on consecutively in this series of papers.

    – 164 –

    compressed branchlets, shorter fewer-flowered, racemes, glabrous pedicels, and smaller dehiscent pod, with much stouter beak, which contains not 1–3 but 2–5 seeds. From Carmichaelia prona, the only purely prostrate species yet described, it is distinguished at once by its leafless adult branches, dehiscing pod with longer beak and greater number of seeds.

    Except for the dehiscence of the pod, the species under consideration would come into the subgenus Huttonella.

    The plant was discovered by Mr. W. H. Field, M.P., to whom it is dedicated. Mr. Aston was with Mr. Field at the time of the discovery, and he kindly handed over to me for publication the material he had collected, gave me two living plants for cultivation and further observation, and supplied the information given above regarding the habitat and habit of the species.

    26. Carmichaelia grandiflora (Benth.) Hook. f. var. alba T. Kirk.

    The var. alba of Carmichaelia grandiflora was established in 1899 by T. Kirk to accommodate a plant which grows abundantly near the outskirts of subalpine Nothofagus forest in the neighbourhood of the junction of the White River and the main branch of the River Waimakariri, not far from their sources (Western Botanical District). There it has been collected by Kirk himself, Cheeseman, Wall, myself, and others. Cheeseman (Manual, p. 115) recognizes only the “type”—obviously a mixture—and var. divaricata T. Kirk, but (Illustrations of the New Zealand Flora, facing pl. 33) he writes regarding C. grandiflora, “It is an exceedingly variable plant. Mr. T. Kirk in his ‘Students' Flora,’ enumerates three varieties, and there are other distinct-looking forms. These varieties* differ in size, in the mode of branching, and in the size and shape of the pod. But before their systematic position can be properly understood they all require careful study and examination in the field.” From this it is evident that, according to Cheeseman, the “varieties” of C. grandiflora differ from one another in virtually all the essential characters used to define the species of Carmichaelia.

    Coming to var. alba, this is probably now accepted by Cheeseman as a variety, since in the Illustrations, when criticizing Kirk's remarks about its odour, Cheeseman writes, “Mr. T. Kirk in the ‘Students' Handbook’ says that the flowers ‘smell disgustingly of mice.’ But this peculiarity, so far as my own observations go, is only noticeable when the plant is being dried. In the fresh state the odour of the flowers is decidedly pleasant.”

    Since there is blossoming just now in my garden (30th December, 1917) a plant of the variety under consideration, collected for me last year by Professor A. Wall, M.A., from the original locality of the plant, I am in a position to add a few details about the variety from living material, which, unless being slightly less luxuriant and blooming more scantily, is essentially the same as if gathered from a wild plant.

    Kirk describes his var. alba as follows: “Branchlets more robust, compressed, deeply grooved, fastigiate or nearly so. Flowers as in the typical form, but white. Ripe pods not seen. Smells disgustingly of mice”; and he adds that it is “possibly a distinct species.”

    The plant in my garden is certainly not “fastigiate”; on the contrary, the branches are wide-spreading, being 60 cm. in their spread, while the shrub is but 30 cm. high. The branches are dark green, flattened, about

    [Footnote] * It is not clear whether the author means only Kirk's published varieties or these together with the “other distinct-looking forms,” but I think the latter are meant to be included.

    – 165 –

    3.5 mm. diameter throughout for their final 15 cm. of length, grooved but not nearly to the same extent as in dried material, and more or less arcuate. The branchlets vary from about 4 cm. to 15 cm. in length; they are inserted on the flanks of the branch at an angle of about 30° and at about 2.5 cm. distance from one another. They are straight, bright yellowish-green, striate, flat, 3 cm. wide more or less, and almost uniform in width throughout. The leaves are numerous where sheltered, and then in fascicles of 2–4 at the base of young stems; elsewhere they are inserted in the notch of the stem at an angle similar to that of the insertion of the branchlet; the largest are about 1.8 cm. long, 3-foliate, their petiole 7 mm. long and channelled above; the leaflets are uniform in size, rather dull green, obcordatecuneate, their midrib sunken above but slightly keeled beneath; other leaves have similar characters, but they gradually decrease in size towards the tips of the branchlets until they become only 5 mm. long, or even less, and may consist of one leaflet only. In the cultivated plant the leaves are glabrous, but wild specimens show a few hairs on the under-surface, especially on the midrib. By all previous authors C. grandiflora is described as having glabrous leaves, but in all my herbarium specimens collected in various localities, including the classical habitat, Milford Sound, the under-surface of the leaf is more or less hairy, and sometimes considerably so. The flowers are white, except for a distinct pale-purple blotch through the median line of the standard, and honey-scented but rather cloying; they are in lax-flowered racemes, about 16 mm. long, furnished with short peduncles 4 mm. long or less. The calyx is campanulate and 3 mm. long; its tube is green or mottled pale purple, and the teeth are acute, small, pale purplish-brown, and ciliolate with white hairs. The standard slightly exceeds the keel, being 6 mm. long by 6 mm. broad; the wings and keel are equal in length (5.5 mm.).

    The above description corresponds, as far as changes through drying allow a comparison to be made, with that supplied by dried specimens. The var. alba may therefore be defined as follows: A wide-spreading shrub with the branchlets situated on the flanks of the stems, the racemes numerous, 4–6-flowered, the flowers white with a pale-purple blotch down the centre of the standard and sweet-scented, the standard as broad as long and rather longer than the keel, which equals the wings.

    Up till now C. grandiflora var. alba has been recorded from its one original station only. But that it has so restricted a distribution seems highly unlikely. It is more than likely that through taxonomists working mainly with dried material the colour of the flowers has been frequently overlooked, and that specimens are now included in herbaria along with the “type,” or other possible varieties, which may agree in colour with var. alba. How greatly colour has been neglected in diagnoses of species of Carmichaelia is demonstrated by the facts that Kirk mentions colour specifically in only four out of twenty-three species (Huttonella included) and that Cheeseman refers to colour in only seven out of nineteen species.

    27. Carmichaelia juncea Col. ex Hook. f. (var. from Upper Clarence Valley).

    Carmichaelia juncea Col. was described in the first place by J. D. Hooker in the Flora Novae-Zelandiae, vol. 1, p. 51, from specimens collected by Colenso from “east coast, Hawke's Bay and Taupo.” In the Handbook Hooker referred plants from the East Cape (coll. Sinclair), from Akaroa (coll. Raoul), and from the Canterbury Plains (coll. Travers) to this species.

    – 166 –

    Petrie in his list of Otago plants (Trans. N.Z. Inst., vol. 28, p. 546, 1896) recorded C. juncea from various localities in what I now call the “North Otago Botanical District.” Shortly afterwards, Kirk in the Students' Flora accepted Petrie's determinations, and, as will be seen, enlarged Hooker's original conception of the species. Finally, Cheeseman, in the Manual, followed Kirk but gave a fuller description of the species than had been published up to that time.

    Both Kirk and Cheeseman agree in considering that the Otago plant may belong to an undescribed species, basing their opinions chiefly on the size of the pod and position of its beak.

    On the 9th December, 1917, Mr. Christensen noted a Carmichaelia growing on the bank of the River Clarence (North-eastern Botanical District), between the roads leading to Jack's and Jollie's Passes, which he described as “a bush 2 ft. to 3 ft. in height, with the branches drooping over the water.” He very kindly sent me specimens, one showing immature flowers (for the most part) and the other abundance of leaves. Towards the end of the month he again went in quest of fully opened flowers, and sent me a large living specimen fully in bloom, which is now growing in my garden.

    The above specimens I have been able to compare with Petrie's North Otago plant and with Colenso's type specimens of the species. Below I give a full description of the Clarence Valley plant. It appears to come into the conception of the C. juncea of Cheeseman's Manual, but it differs from both the type and the Otago plant in the racemes never being in fascicles, the glabrous calyx, and the much longer calyx-teeth. I have not yet seen the pod.

    As for the calyx-teeth, they are different in the three forms. In the type they are so small as to be almost wanting; in the Otago plant they are small but quite distinct, and broad at the base; in the Hanmer plant they are comparatively long and narrow. Other distinctions between the three forms may be noted on comparing the following description with Hooker's, Kirk's and Cheeseman's diagnoses.

    Until fruiting specimens are received, and perhaps comparison made with living material from Hawke's Bay and Otago, which I am hoping to secure, it seems best to let the matter of Carmichaelia juncea remain as Cheeseman has left it. But there seems little doubt that the species as at present constituted is an aggregate, with distinct varieties of restricted distribution. As regards the Akaroa and Canterbury Plains plant I know nothing.

    Description of Carmichaelia juncea var. from the Upper Clarence Valley.

    A low shrub 60–90 cm. high, with abundant slender drooping branches and numerous short racemes of small sweet-scented flowers.

    Branchlets numerous, close-set, passing from stem at a very narrow angle, bright green, compressed, but oldest branches terete, 2–3 mm. broad or rather broader but gradually tapering to an extremely narrow apex, usually leafless, glabrous. Leaves on younger branches, 1–3-foliate, ± 16 mm. long, petioles up to 6 mm. long; leaflets variable in shape and size, frequently oblong or ovate-oblong but occasionally obovate, linear, & c., retuse, bright green, glabrous above but somewhat hairy beneath with short appressed hairs, lateral leaflets much smallest, terminal ± 9 mm. long. Racemes solitary, apparently never fascicled, ± 6 mm. distant, 4–12-flowered but not dense, up to 12 mm. long; pedicels and rhachis

    – 167 –

    slightly pubescent especially when young, pedicel at most equalling the calyx, pale-coloured. Flowers minute, about 3.5–4 mm. long; calyx campanulate, glabrous, 2 mm. long (to tip of tooth), pale yellowish-cream dotted pale purple, teeth narrow, acute, rather long, dark purple; standard about 3 mm. long by 4 mm. broad, upper surface cream-coloured on lower half, above dark purple marked with almost black lines passing obliquely from median line of leaf, paler beneath, slightly exceeding the keel; wings cream-coloured more or less tinged yellow, equalling keel, oblong, rather narrow; keel near apex dark purple, beneath yellowish to cream-coloured.

    28. Carmichaelia Monroi Hook. f.

    Two years ago Mr. B. C. Aston, F.I.C., while investigating the flora of the Clarence River basin, collected a supposedly undescribed species of Carmichaelia a description of which is given below. The examination of Aston's material led me to a comparison with that in my herbarium of C. Monroi Hook. f., with the result that the Clarence Valley plant may be the true C. Monroi, and that the forms included by Kirk, Cheeseman, and others under that name may be either one or two undescribed species or very distinct varieties of C. Monroi. This conclusion is quite unexpected, for few species in the flora seemed to be better understood than is C. Monroi.

    Description of Aston's Clarence Valley Species of Carmichaelia.

    A stout rupestral much-branched shrub with spreading, more or less drooping, leafless branches, up to 60 cm. long. Branchlets rigid, green, flat, grooved, ± 12 cm. long and up to 9 mm. wide, hoary pubescent when young with short appressed hairs which also extend at times to the older branchlets. Racemes ± 5 cm. long, frequently 7-flowered; rhachis and pedicels densely pubescent with appressed white hairs; pedicels slender, about 6 mm. long. Flowers about 10 mm. long. Calyx campanulate, densely hairy, 5 mm. long; teeth 3 mm. long, narrow-triangular, acute, standard rather longer than the keel, 10 mm. long, 7 mm. broad, ? cream with large purple blotch in centre whence ? purple lines radiate to margin and apex; wings 6 mm. long, 2.5 mm. broad, marked with ? purple lines; keel 9 mm. long, blotched with ? purple near apex and marked with ? purple lines. Pods 12–17 mm. long, black when ripe, turgid; valves wrinkled; beak oblique (straight in one specimen), usually short but up to nearly 3 mm. long; seeds pale brown mottled with black, rather large, 3 mm. long.

    South Island: North-eastern Botanical District—On shaded faces of limestone cliffs in various gorges on the south-eastern side of the Inland Kaikoura Mountains. B. C. Aston!

    Had this limestone-cliff plant been the only species of Carmichaelia in its immediate locality, its altogether different habit, together with its much longer and wider branches and hoary branchlets, its 7-flowered racemes, and its larger flowers, would separate it from any forms of C. Monroi as at present understood. But on stony debris, in close proximity to the rock-plant, but in the open, Mr. Aston collected specimens of a Carmichaelia with short close branchlets like those of C. Monroi of the Manual except that they are pilose as in the rupestral plant. Unfortunately their pods, & c., are too immature in the specimens at my disposal for further comment.

    The type of Carmichaelia Monroi Hook. f. was collected by Monro “from half-way up to the summit of Macrae's Run” (Awatere River basin):

    – 168 –

    Handbook of the N.Z. Flora, p. 49. Hooker's description is very short and inadequate. But the branchlets are described as glabrous, while the flowers are smaller than in the above rupestral plant. Considering that Garmichaelia Monroi Hook. f. and the Clarence Valley plant grow on opposite sides of the same range of mountains, and that the ecological conditions of both areas are not very different, it seems fair to offer the suggestion that perhaps Hooker neglected to note the hairy branchlets of the Awatere plant, and that the groups here discussed are not distinct, but one and the same. But this question can alone be decided by comparing Awatere and Clarence Valley material and growing both rupestral and debris plants from seed and then cultivating the seedlings under identical conditions.

    Coming next to Carmichaelia Monroi in the sense used by Kirk and Cheeseman, this is invariably a low-growing shrub with dense erect branch-lets forming open flat cushions on stony ground. But an examination of the material of this species at my disposal and a comparison with the descriptions of Hooker, T. Kirk, and Cheeseman respectively have led me to the opinion that more than one varietal group is included. For instance, Petrie's Otago specimens have glabrous calyces—a marked contradistinction to Hooker's description of his Awatere specimens as having a “hoary” calyx. Also, specimens collected by me in the Eastern Botanical District have almost tomentose calyces, while Cheeseman describes the calyx as “silky, sometimes densely so,” but he does not suggest that it is ever glabrous. These Otago specimens, too, have triangular, but not narrow-triangular, calyx-teeth as given by Cheeseman, while the Eastern Botanical District plant has small calyx-teeth.

    From the above it seems clear that the Otago plant at least should be separated from its allies as a variety, but I do not propose to take this step until the taxonomy of the whole group is made clear.

    Again, there is an allied but much taller plant than the above cushion-form. This I have collected at Riversdale (Waimakariri River basin) and on the Waimakariri River bed on the Canterbury Plain near the protection-works. A specimen was planted by me in the gardens of the Biological Department, Canterbury College, but, unfortunately, before I could describe it, it was killed during the building of the new chemical laboratory. Another living plant was for many years in the old “native section” of the Christ-church Botanical Gardens, and it may still be there. Also, there is in my herbarium, under the MS. name Carmichaelia humilis, a specimen collected by Mr. Petrie in the North Otago Botanical District.

    To sum up, there is a group of more or less low-growing forms of Carmichaelia closely allied to and including Hooker's original C. Monroi which does not consist of a number of identical individuals, but of minor groups distinguished from one another by well-marked characters, so that the major group is either a collection of closely allied species one of which is Carmichaelia Monroi, or this latter should be treated as an aggregate species consisting of perhaps five quite distinct varieties.

    29. Cassinia albida (T. Kirk) Cockayne.

    In Trans. N.Z. Inst., vol. 38, pp. 368–69, 1906, after considerable experience both with Cassinia Vauvilliersti Hook. f. and the var. albida T. Kirk, I proposed to rank the latter as a species. Cheeseman (Trans. N.Z. Inst., vol. 39, p. 446, 1907), criticizing my procedure, said that the course to be followed in this matter would “depend largely on the point of view and personal judgment of the observer, coupled, of course, with a full consider-

    – 169 –

    ation of the evidence available.” More recently Cheeseman (Illustrations of the N.Z. Flora, facing pl. 107) accepts C. albida as a species.

    With my views as to the relations of species and variety greatly changed since 1906; I would now reverse my decision, were it not that both C. Vauvilliersii and C. albida embrace more than one microspecies, and that if the latter were reinstated as a variety of the former it would be necessary to establish subvarieties in addition to varieties, so overburdening the nomenclature.

    In Trans. N.Z. Inst., loc. cit., a var. canescens of Cassinia albida is defined by me. This is distinguished from the type, to which the distinguishing varietal name “typica” is here given,* by the leaf being so densely covered on the upper surface with a mat of white hairs as to look as if powdered with dust or mildew.

    Some time ago Professor A. Wall sent me living plants of both varieties. These cultivated in my garden have put forth many young shoots, which maintain their distinguishing varietal characters, though in var. canescens the hoariness is somewhat less marked. Both varieties are confined to the North-eastern Botanical District, but recent observations of Wall show that possibly neither variety extends to its southern boundary.

    In addition to the two varieties dealt with above, Mr. Aston two years ago collected in the Clarence Valley a variety of Cassina albida which is woolly on the under-surface of the leaf and rather more hoary on the upper surface than is var. canescens. But, as I have only the one specimen, I merely call attention to this apparently distinct form.

    It is a matter of interest that on the Lord Auckland Islands the closely related Cassinia Vauvilliersii (Homb. & Jacq.) Hook. f. is represented by two varieties—viz., the type and one with a canescent upper surface to the leaf. These characters are so striking that the two varieties can be recognized at a distance.

    30.

    Epilobium chloraefolium Hausskn.

    This extremely common subalpine species was first described by Haussknecht in 1879 from dried material (Oestr. bot. Zeitschrift, vol. 29, p. 149). Although, as Haussknecht points out, the species bears no resemblance to E. rotundifolium Forst. f., the dried material which he examined in various English herbaria showed him that it had been referred to the latter. But long after Haussknecht's subjecting the New Zealand Epilobia to a searching inquiry—indeed, up to the publication of Kirk's Students' Flora in 1899—with but few exceptions, the New Zealand Epilobia, now known to number at least thirty-eight species, as well as some strongly marked varieties, had been crammed into the Procrustean bed of Hooker's arrangement in the Handbook, where but seventeen species were admitted. This summary

    [Footnote] * Cassinia albida (T. Kirk) Cockayne var. typica Cockayne var. nov. Foliis supra pilis sparsissime obtectis.

    [Footnote] † See L. Cockayne, The Ecological Botany of the Subantarctic Islands of New Zealand, The Subantarctic Islands of New Zealand, vol. 1, p. 216, 1909.

    [Footnote] ‡ Since the publication of the twenty-eight species admitted by Cheeseman in the Manual the following have been described either as new or “restored”: Epilobium antipodum Petrie. E. arcuatum Petrie, E. cinereum A. Rich. (to replace E. junceum Sol. in part), E. Cockaynianum Petrie, E. erectum Petrie (to replace E. junceum var. macrophyllum Hausskn.), E. hirtigerum A. Cunn. (to replace E. junceum var. hirtigerum). E. nerterioides A. Cunn., E. pedunculare A. Cunn., E. rubro-marginatum Cockayne, E. tasmanicum Hausskn. (the last two to replace E. confertifolium Hook. f. so far as it applied to plants other than those of the New Zealand Subantarctic Botanical Province).

    – 170 –

    treatment was for the most part due, I believe, to Hooker's statement in the Handbook (p. 76), as follows: “I have repeatedly studied the New Zealand ones [Epilobia], many of which completely puzzle me. The following descriptions represent in many cases perhaps prevalent forms rather than species; and the student will certainly find intermediates between most of them. It is useless attempting to name many species until copious suites of specimens are collected, the characters being to a great extent comparative.”

    Cheeseman's description of Epilobium chloraefolium in the Manual is excellent. However, he states (p. 178) that, though a well-marked plant, it is “at the same time a very variable one, especially in height, degree of branching, size of flowers and capsules, & c.” But this-variability depends, so far as my investigations go, not upon there being a number of true-breeding races (microspecies) included in either Cheeseman's or Haussknecht's groups, but rather upon true variability according to environment—shade- and sun-plants, for instance, differing greatly in certain particulars. Also, I rather suspect that certain hybrids are included by Cheeseman in his group.

    In this note I am suggesting an enlargement of the conception of the species by adding a distinct true-breeding group which, although it fits well into the original description if size of organs is ignored, far surpasses the type in this respect. I am also giving a varietal name to the “type,” so that to those accepting my conclusions the group E. chloraefolium will consist of the two varieties and of any other allied varieties which may be segregated from the individuals now constituting the species, or in course of time be discovered.

    (a.) Epilobium chloraefolium Hausskn. var. kaikourense Cockayne var. nov.

    Habitu robustiore, floribus duplo majoribus a typo differt.

    This well-marked variety is distinguished at a glance from any form of Epilobium chloraefolium by its exceedingly robust habit and large white flowers, which at times are quite 28 mm. in diameter when fully opened.

    The stems, decumbent at first, finally erect and woody in their older parts, are stout, purple, shining, smooth, and minutely bifariously pubescent. The leaves are numerous, moderately close-set, pilose especially on the margin at the base and on the petiole when young but finally glabrous, rather thick, coriaceous, somewhat glossy, bright- or yellowish-green above, often reddish beneath, and taper into a short, broad, channelled petiole about 4 mm. long; the lamina is more or less broadly oblong or even elliptic, about 20 mm. long by 12mm. wide and distinctly but minutely toothed, its apex is obtuse, the midrib is strongly keeled, and the lateral veins distinct.

    The flowers are few in the axils of the terminal leaves, white, invariably large, and often attain 28 mm. diameter. The plant continues blooming for more than six months. The capsule is about 3.3 cm. long, dark purple, minutely pubescent; its peduncle is only 3.5 mm. long—i.e., it is much shorter than the subtending leaf, which may be 19 mm. long or longer. The seeds are numerous, ± 1.75 mm. long, light-brown, and papillose.

    The great differences in appearance which the above – described vars. of E. chloraefolium present made me inclined at one time to consider the var. kaikourense a distinct species, especially as it came true from seed and occupied a special limited area of distribution. So long ago as 1892 Mr. T. Kirk wrote to me regarding a specimen (herb. L. Cockayne, No. 3668) I submitted for his opinion, “May prove distinct, but further specimens must be examined—a very interesting form.”

    – 171 –

    A careful comparison of living plants of both varieties in my garden shows that there is no important difference between them except size, while the structure of the flower is identical in both.

    The plant was found in the first instance by myself in 1892, growing in rather moist soil on cliffs a little distance from the sea at Kaikoura, and shortly after that I found it to be abundant under the subalpine scrub on Mount Fyffe (Seaward Kaikoura Mountains). Plants were cultivated in my New Brighton garden, where they, or their seedlings, remained for six years at least; and seeds were sent in 1897, and probably earlier, to various European botanical gardens under the name Epilobium Cockaynianum* Petrie ined., but which Petrie never published. In 1905 Mr. H. J. Matthews and myself again observed the plant on Mount Fyffe, and I recorded its occurrence in Trans. N.Z. Inst., vol. 38, p. 373, 1906, as Epilobium sp. aff. E. chloraefolium Hausskn. Since then the plant in question has been found by Mr. C. E. Foweraker and myself in the Awatere Valley, by Mr. B. C. Aston in the Clarence Valley, and by Professor A. Wall on the Seaward Kaikoura Mountains; while a plant from Mount Isabel, at Hanmer, collected by Mr. C. E. Christensen probably is var. kaikourense. In other words, the variety is confined to the North-eastern Botanical District, where it is of wide distribution from sea-level to at least 900 m. altitude, and grows on rock, beneath shrubs, and probably in shady tussock grassland.

    Phytogeographically the distribution of E. chloraefolium var. kaikourense is an interesting case of a true-breeding race of a species of wide distribution being confined to a limited area which possesses a special ecological character, as reflected in the great number of locally endemic plants.

    From the horticultural standpoint, the ease of culture of the plant, its general habit, beautiful long-blooming flowers, and purplish foliage and stems render it worthy of any rock-garden; nor is there fear of its becoming a weed, as in the case of certain New Zealand Epilobia.

    (b.) Epilobium chloraefolium Hausskn. var. verum Cockayne var. nov.

    This equals E. chloraefolium as described by Haussknecht in Monographie der Gattung Epilobium, p. 299, Taf. 19, fig. 81, 1884. No further description is needed. The differences between var. verum and var. kaikourense are given above.

    31. Epilobium pedunculare A. Cunn. var. brunnescens Cockayne var. nov.

    Caulibus pallidis saepe brunneis tinctis. Foliis ovato-oblongis vel oblongo-rotundatis, supra pallide viridibus saepe brunnescentibus, margine remote dentatis, subtus purpurascentibus. Capsulis glaberrimis, pallide bruneis, ± 5.3 cm. longis; pedicellis colore capsulis etiam, multo elongatis, 6.6 cm. longis.

    This variety forms large more or less circular patches. The leaves vary in size, but about 9 mm. long is frequent; the petioles are about 3 mm. long. Where exposed to bright light the leaves assume a brownish tinge. The flowers are small, white, and about 5 mm. diameter. The calyxsegments are narrow-oblong, 3 mm. long, brownish, and end in a swollen purplish apex. The capsule is more than three times the length of the ovary, and the peduncle increases from about 2.2 cm. to 5.7 cm. as the capsule develops.

    [Footnote] * E. Cockaynianum Petrie in Trans. N.Z. Inst., vol. 41, p. 140, 1909, has no relationship to this, but is related to E. alsinoides A. Cunn.

    – 172 –

    Epilobium pedunculare var. brunnescens has a wide range, but this I cannot at present define, nor its ecological distribution. However, I have plants in my garden identical in every particular collected from localities far distant from one another—viz., Mount Egmont (coll. L. C.) (EgmontWanganui Botanical District) and Four Peaks (coll. A. Wall) (south of the Eastern Botanical District).

    Haussknecht describes a var. laxa of E. pedunculare, and it may be that my new variety is the same. But without actually comparing the material on which Haussknecht founded his variety it is impossible to come to a conclusion, so it seems to me better to risk the establishment of a synonym, which for a time will serve a definite phytogeographic purpose, than to withhold publication or refer the group to var. laxa, which it may not be after all.

    The further question arises, am I right to uphold the species Epilobium pedunculare A. Cunn. rather than follow Hooker, Kirk, and Cheeseman, and deal with it as a variety of E. nummularifolium?

    Haussknecht—relying only, however, upon dried material—keeps the two species distinct, and strongly supports his position by the two fine figures 94 and 96 (Monographie der Gattung Epilobium, Taf. 22 and 23). He also states that in herbaria E. pedunculare is frequently found mixed with E. nummularifolium, but that they are readily distinguished by E. pedunculare having the leaves smaller, more close-set, thicker, entire, and with shorter stalks; the capsule glabrous and its peduncle more slender, and the seeds covered much more thickly with papillae (i.e., p. 303—freely translated).

    My own experience, after many years' observation of various groups included under the specific names nummularifolium and pedunculare, both growing in many parts of New Zealand and also cultivated by me, has convinced me that the two species are absolutely distinct, and separated by well-marked unchangeable characters.

    Epilobium nummularifolium, in one form at any rate—and the species may quite well contain only the one form—is common throughout the North and South Islands, but absent in Stewart Island; it appears to be mainly a lowland plant, but there is no exact record of its distribution, such being confused with that of E. pedunculare, which ascends at least to the subalpine belt.

    E. nummularifolium may be best distinguished from the aggregate E. pedunculare by its orbicular or suborbicular bright-green leaf with at times a more or less truncate base, its rather long petiole which is winged above, its capsule not glabrous but closely covered with a short cinerescent pubescence, its fruiting peduncle not lengthening so greatly as in E. pedunculare, and its less papillose seeds. Even the leaves alone of living specimens enable the two species to be identified in an instant.

    32. Epilobium pedunculare A. Cunn. var. minutiflorum Cockayne var. nov.

    Varietas distinctissima, caulibus gracilibus rubro-purpureis, foliis parvis rotundis subrotundis vel ovatis viridibus, floribus minutis, pedunculis statu fructu solum 3 cm. longis et capsulis purpurascentibus brevibus 11 mm. longis facile distinguenda.

    South Island: Eastern Botanical District — (1) Trelissick Basin, but details regarding habitat wanting: A. Wall ! (2) Rakaia River bed not far from mouth of river: H. H. Allan !

    – 173 –

    The above variety is described from a plant which has been in my garden for only a few weeks, collected by Professor Wall as above.

    The plant forms matted patches. The leaves vary in size from less than 3 mm. long up to about 5mm. The reddish-purple stems, petioles, and peduncles contrast with the bright-green leaves. The flowers are white; the calyx is pale brown tinged and margined with reddish-purple; the petals are white; the slender petiole only increases from 2 cm. to 2.5 cm. when the capsule is ripe.

    33. Epilobium pedunculare A. Cunn. var. viride Cockayne var. nov.

    Caulibus teneris pallide viridibus; foliis oblongis vel rotundatis remote et obscure dentatis, laminis usque ad 7 mm. diam.; floribus 6.5 mm. diam., pedunculis brevibus 5–11 mm. longis; capsulis circ. 2.8 cm. longis; viridibus secundum suturam brunneo tinctis.

    North Island: North Auckland Botanical District—On river-bed near Fairburn, Mangonui County. H. Carse !

    This variety is readily distinguished from E. pedunculare var. brunnescens by its green leaves and stem and by the much shorter peduncle of the flower, which does not elongate to nearly the same length as that of var. brunnescens in the fruiting stage. The flowers and capsules are also smaller.

    The plants now growing in my garden, from which the above diagnosis is drawn up, were collected specially for this paper by Mr. H. Carse as an example of the form of Epilobium pedunculare in his neighbourhood. Whether the above variety is identical with the plant originally described by Allan Cunningham I cannot say, for the original description is quite general and would fit almost any variety of the species.

    34. Gunnera densiflora Hook. f.

    In 1864 Hooker published his Gunnera densiflora, basing his description on specimens collected by W. T. L. Travers at an altitude of 4,000ft. in the Acheron and Clarence Valleys—i.e., it must have been collected not far from the sources of these rivers if the altitude as given is correct. For some thirty-two years no Gunnera was discovered that could be referred to the above species until, in 1896, I collected a species of Gunnera in the Craigieburn Mountains (Eastern Botanical District), at the headwaters of the Hogsback Creek, at an altitude of rather more than 900 m. Specimens were sent by me to Kirk, who referred them, apparently without hesitation, in his Students' Flora (1899) to G. densiflora. Cheeseman, in the Manual, working with the same material as Kirk, drew up a new diagnosis of the species based partly upon Hooker's original brief description and partly upon my not-too-well-prepared specimens. Regarding these latter Cheeseman writes that they “are the only ones I have seen that can be referred the species.”

    So the matter remained until, in 1911, Mr. R. M. Laing, M.A., B.Sc., during a botanical excursion towards the headwaters of the Rivers Clarence and Waiau, discovered, in abundance, on the western side of Lake Tennyson a species of Gunnera which, in my opinion, is equivalent to the plant on which Hooker founded G. densiflora.

    Mr. Laing submitted his material first of all to Cheeseman, who suggested that it might quite well be Gunnera cordifolia Hook. f., hitherto thought to be confined to Tasmania. Later, Mr. Laing submitted specimens for my opinion, telling me also what Cheeseman had said. G. cordifolia

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    is well illustrated in Das Pflanzenreich (IV. 225. Halorrhagaceae, p. 108, fig. 31). After examining Mr. Laing's specimens, and comparing them with the above-cited figure, & c., I came to the conclusion that the species was either G. cordifolia or a variety of that species, and so dealt with it in my unpublished Vegetation of New Zealand.

    Laing (Trans N.Z. Inst., vol. 44, pp. 65–66, 1912) drew up a detailed description of the Gunnera in question in the field with the living plant before him, and his and my original opinions are considered below.

    Regarding the Craigieburn Mountains plant, Laing stated (i.e., p. 66) that Cheeseman had informed him it was distinct from the Lake Tennyson plant, and that it had been identified by the Kew authorities as Gunnera densiflora Hook. f.

    Learning recently that Professor Wall intended paying a botanical visit to the Trelissick Basin, I explained to him as exactly as I could—no easy matter—the precise spot where I had collected the Gunnera in 1896, and urged him to make a thorough search. This he most willingly did, and not only found the plant in quantity in the locality indicated, but discovered other stations for it in the neighbourhood. He secured ample material, of which he sent me abundance both living and dried, some of the former being now growing in my garden. As it is a matter of considerable phytogeographical importance to get detailed knowledge of this rather critical species of Gunnera I am publishing a description.

    Description of the Gunnera from the Craigieburn Mountains.

    Rhizome short, ± 19 mm. long by 5.5 mm. thick, rooting with straight roots about 8 mm. long, and giving off stout, terete, dark-brown, more or less strigose-pilose stolons each about 3 cm. long and 2 mm. diam. Leaves in rosettes of about 4 or 5 ± 3.5 cm. across; petiolate with petiole variable in length from about 2–2.8 cm., fleshy, pale often tinged pink, terete or channelled above or only near junction with lamina, pilose with strigose white hairs on back and margin but variable in this respect as to density of hairs on different leaves of same plant; lamina moderately bright green, coriaceous, usually more or less cordate at base, sometimes truncate, auricled at base with two small toothed appendages ± 2 mm. long which are bent upwards, orbicular or broadly ovate-orbicular, hairy above and on margin, glabrous beneath, rounded at apex or occasionally almost subacute, rather coarsely but sharply toothed with about 9 teeth ± 1 mm. long on each side, veins evident above and beneath, midrib stout and keeled beneath.

    Flowers unisexual, numerous. Male flowers in spikes about 2.5 cm. long terminating rather stout scapes about 2.8 cm. long arising from axils of leaves and densely covered with brown strigose hairs; pedicels very short, subtended by a small narrow subulate bract about 2mm. long; calyxlobes 2, narrow-triangular, about 1 mm. long; petals 2, transverse, narrow linear-spathulate, much exceeding anthers, 4 mm. long and 0.5 mm. wide near the black acute apex; stamens 2, situated on base of petals, broadly ellipsoid, 2 mm. long, rounded at apex, filaments extremely short. Female crowded into a dense globose head about 6 mm. long terminating a stout, fleshy, pale or pale-brown scape 10 mm. long, pilose with numerous white hairs; calyx-tube urceolate, pale green, smooth, about 2 mm. long; calyxlobes 2, subulate, purple with black tip, about 0.75 mm. long. Styles 2, wide-spreading, pale brown, 4–5 mm. long, stigmatic throughout.

    On compa ing, detail by detail, the above description with that of Laing (for the Lake Tennyson plant), of Schindler (for the Tasmanian plant),

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    and of Hooker (for the type of Gunnera densiflora), my opinion is that the New Zealand plants are all one and the same, and that the Tasmanian may also belong to the same species. On the other hand, the New Zealand Gunnera, accepting Schindler's description and illustration of the Tasmanian, differs from the latter in the petals, which are much longer and narrower in the New Zealand than in the Tasmanian plant, and in the shape of the drupe, pyriform in the New Zealand, ovoid according to Hooker ex Schindler in the Tasmanian plant. Also Schindler's figure shows the margin of the leaf of his plant as strongly ciliated, whereas in the New Zealand plants the ciliation is virtually confined to young leaves. Bearing the above in mind, it seems best to maintain Gunnera densiflora as a species, but to remember that it is extremely closely related to G. cordifolia Hook. f. of Tasmania, and is a further link between the floras of the eastern Australian and New Zealand regions.

    35. Haastia recurva Hook. f. var. Wallii Cockayne var. nov.

    Foliis et capitulis quam illa typi minoribus; plerumque pilis albidis munitis sed eis prope ramulorum apices interdum subfulvidis tinctis; bracteis involucri apiculatis.

    The variety differs from any example of Haastia recurva that I have seen hitherto in the much smaller size of all its parts, in its dense wool being white nearly everywhere and only slightly fulvous near the apices of the branchlets, and in the apiculate apex of the involucral bracts. The leaves are generally less than 10 mm. long, or only half the length of good-sized leaves of the type. The flower-heads are 7 mm. diam., or not half the size of medium-sized heads in the type.

    The plant was collected by Professor A. Wall on a shingle-slip near the summit of Mount Fyffe, Seaward Kaikoura Mountains. Unfortunately, only the one plant was noted. On receiving the specimen I thought this plant with white wool and slender branches might be the common form of the Kaikoura Mountains in general, but upon comparison with Mr. Aston's specimens from Mount Tapuaenuku (Inland Kaikoura Mountains) this apparently is not the case. Specimens from Shingly Range (Awatere) also belong to the type.

    36. Haastia Sinclairii Hook. f.

    Judging from specimens in my herbarium, there appear to be two distinct groups of plants included under Haastia Sinclairii Hook. f. by Cheeseman (Manual, p. 321). One of these groups is figured in Cheeseman's Illustrations of the N.Z. Flora, pl. 100, and this appears characteristic of the species so far as the North-western and Western Botanical Districts are concerned; but the Fiord Botanical District group appears to differ in certain particulars as compared with the more northern plant, especially in its smaller leaves, which are covered beneath much more thinly with fulvous (not white) wool, and above are thinly covered with wool or, at times, almost glabrous. Also, the heads of the Fiord plant are much smaller. I do not propose here to separate the species into two varieties, the intention of this note being to call the attention of collectors in the area of the species to probable differences in plants of this species which they may find.

    In the Illustrations of the N.Z. Flora Cheeseman comments upon the distribution of Haastia Sinclairii as follows: “H. Sinclairii, which is a true ‘shingle-slip’ plant, never found away from the slopes of dry shingle which form such a prominent feature on the eastern side of the Southern Alps.”

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    And farther on—“But it was soon found to have a wide distribution on the eastern side of the Southern Alps, and is now known to extend from the northern portions of the Mount Arthur Range southwards through the Canterbury Alps to the south-west of Otago…. I am not aware, owever, that it occurs in any locality well on the western side of the watershed of the Alps.”

    The above statements, though topographically true in our present state of knowledge, neglect the ecological viewpoint. There are two distinct classes of shingle-slips—the one very dry on the surface and situated beyond the average limit reached by the western rainfall, and the other not by any means so dry a station, since it lies within the wet area. These two classes of shingle-slip are clearly defined by their plant inhabitants. A dry or eastern shingle-slip contains that wonderful assemblage of which the following, to cite only a few, are characteristic: Craspedia alpina, Notothlaspn rosulatum, Poa sclerophylla, Ranunculus Haastii, Stellaria Roughii, Veronica epacridea. On the other hand, the western shingle-slip contains none of the above species; in fact, there are but few plants common to both—e.g., Epilobium pycnostachyum is one. The species of Haastia, too, are an especially good index. On an eastern shingle-slip (using the term ecologically and not as used in the quotation above) Haastia recurva is alone to be found, but on a western shingle-slip it is absent, being represented by H. Sinclairii. So, too, the dry east gives Veronica Haastii, but once well into the area of excessive rain it is V. Haastii var. macrocalyx.

    As for Haastia Sinclairii not having been found to the west of the actual Divide, I suspect this is chiefly due to the fact that shingle-slip is not much in evidence on the west, speaking comparatively, and also that, the North-western Botanical District excepted, few collections have been made on mountains possessing shingle-slips, these true western mountains being almost entirely unexplored botanically.

    37. Hymenanthera crassifolia Hook. f.

    Hymenanthera crassifolia Hook. f. was originally a mixture of Scaevola novae-zelandiae A. Cunn., now known as Hymenanthera novae-zelandiae (A. Cunn.) Hemsley, and plants from Cape Palliser and Nelson. These latter, along with certain other plants, form H. crassifolia in its restricted sense. But the distribution of the species is uncertain, owing to lack of knowledge as to the limits of polymorphy to be allowed or the variation which takes place not only in H. crassifolia but in the species next dealt with—H. obovata T. Kirk.

    At any rate, so far as I know, true H. crassifolia is found in the Ruahine-Cook Botanical District, on the coast both of the Wellington and Sounds Subdistricts, whence it extends, but not in an unbroken line, to the coast of the South Otago Botanical District. Certain inland plants have been referred to this species, as also a Stewart Island plant, but all these determinations must be received with caution.

    Although there is an admirable plate of H. crassifolia in the Flora Novae-Zelandiae, there is no description easily available which deals with the colour of the flower, and as this is an important character for identification purposes the following description of the flower may prove useful.

    Description of Flowers of Hymenanthera crassifolia Hook. f.

    Flowers inserted on under-surface of twigs, numerous but quite hidden from view on living plant, very small, usually solitary but close-set, hermaphrodite,

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    slightly sweet-scented, pedunculate with decurved or straight green peduncle rather shorter than the flower, furnished with two minute, broadly triangular, scarious brown bracts inserted a little below its centre. Sepals orbicular, about one-half length of petals, green with broad, purplish, minutely fimbriate margin. Petals waxy in appearance, lemon – yellow, oblong, ± 3 mm. long, obtuse, recurved at apex which on margin is sometimes purplish; in bud deeply stained purple.

    The pollen is shed just before the flower opens or shortly afterwards and so easily falls on the stigma. There is no honey. Abundance of pollen reaches the stigma. After pollination the ovary, & c., rapidly enlarges.

    In the neighbourhood of Wellington H. crassifolia commences to bloom some time during the first two weeks of September.

    38. Hymenanthera obovata T. Kirk.

    Hymenanthera obovata, as established by T. Kirk in 1895 (Trans. N.Z. Inst., vol. 27, p. 350), and upheld by Cheeseman in 1906 (Manual, p. 50), is based on material from two sources—the Trelissick Basin (Canterbury) and various localities in Nelson. An examination of the type material in Kirk's herbarium shows that the Trelissick and Nelson material look very different, and the feeling at once arises that the species as at present constituted is a combination of two distinct groups of individuals, each of which is entitled to rank as a species.

    The above difficulty is increased, firstly, by the imperfect knowledge of the flowers of either the Trelissick or Nelson plants, and, secondly, by the discovery by Mr. B. C. Aston, some years ago, of another group of individuals with, it is now known, a local distribution along the shores, & c., of Cook Strait from the French Pass and Kapiti Island to Somes Island in Wellington Harbour. This last-named group far more closely resembles the Nelson than the Trelissick group—indeed, when the flowers of the Nelson group are investigated it possibly will be found either that the two groups are identical, or that they are microspecies which must be united under one name. Likewise, judging from Kirk's type specimens, from my personal knowledge of the genus Hymenanthera in the Trelissick Basin, and from fresh specimens of the plant in question recently collected in the above locality by Professor Wall, it seems not unlikely that the Trelissick group may eventually be referred to H. crassifolia.

    The present state of knowledge regarding Hymenanthera obovata, which I have attempted to concisely indicate, demands that any further knowledge should at once be made available for students and collectors, so that the real status of the species, and of the groups cited above, may be established.

    Thanks to Mr. Aston, who last year (1916) put me in the way of seeing the Wellington plant in more than one locality, and who assisted me in collecting ample flowering material, I am in a position to describe the Wellington plant. Further, Mr. Aston at the close of the year 1917 collected material of the Nelson plant from the Riwaka-Takaka hills, which he has placed in my hands. Finally, Professor Wall has procured for me living and dried material of the Trelissick plant; while Miss Herriott (Biological Laboratory, Canterbury College) sent me some time ago from Cass (Waimakariri River basin) seedlings of the Hymenanthera of that locality, which must be either H. obovata T. Kirk (in part) or H. dentata var. alpina, another group of quite uncertain position.

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    Description of the Wellington Coastal Hymenanthera (= ? H. obvata T. Kirk in its restricted sense).

    A low shrub more or less flattened to the substratum into which its prostrate stems root, but its height varies with regard to degree of exposure of the plant.

    Branches more or less divaricating and interlacing, with younger twigs clad with pale bark covered with a fine pubescence, but older twigs having grey bark dotted freely with lenticels.

    Leaves obovate or oblong-obovate, varying greatly in size according to situation, but from 1 cm. long by 7 mm. wide to 3 cm. long by 1.6 cm. wide are a fair average, though there are others both larger and even smaller, very dark green above, whitish-green beneath, very thick and coriaceous, obtuse, often emarginate, generally entire but occasionally there is a coarse tooth on either side,* above veins obscure, beneath evident but not numerous; petiole short, about 3 mm. long. (In shade reversion-shoots occur with leaves thinner, larger, more irregular in shape, sometimes rhomboid, 1–2-toothed on either side.)

    Flowers numerous, about 4 mm. diam., mostly on the naked branches in the axils of former leaves, solitary or in fascicles of about 4, apparently hermaphrodite, almost twice as large as those of H. crassifolia (see above, No. 37), paler yellow, more urceolate, and margins of petals edged with a bright-purple line; pedicels about 4 mm. long, pale green, fleshy; bract broadly triangular, acute; sepals 4–5 times shorter than petals, much broader than long, green at base but strongly margined with purple, rounded at apex which is fimbriate; petals linear-oblong or narrow ovate-oblong, about 5 mm. long and 2 mm. broad, pale yellow, obtuse, sometimes emarginate, strongly recurved; stamens with orange staminal process; scale (nectary) obovate, slightly praemorse at fimbriate apex, and abundance of honey at base.

    Apart from the much greater size of the leaves, and, where not exposed to the most powerful wind, the much more open character of growth, the above species is distinguished at once from H. crassifolia by the flowers, which are twice as large, the sepals not half length of petals but only one-third or one-fourth as long, the narrower, longer, pale-yellow not lemon-yellow petals.

    With regard to Nelson specimens of undoubted Hymenanthera obovata (in the restricted sense), Aston's specimens are from two sources. The first grows “in crevices of limestone rock at from 2,500ft. to 2,700ft. on the Riwaka Hill, and 1–3 ft. high” (fide Aston). Specimens of this plant show (as described for the Wellington plant) the leaves linear-obovate to occasionally almost linear, very numerous, alternate or fascicled, from more than 4 cm. long to 1.5 cm. or even less, not thick, probably rather dark green above, pale beneath, tapering into a short petiole, entire, rounded at apex. The second was taken from one plant growing at Golden Bay, near the cement-works. It was a “shrub with trunk about 10 ft. high and pendulous branches growing in shade on limestone country” (fide Aston). This specimen has leaves up to 7.5 cm. long, some are 3 cm. broad, quite small leaves are rare. They are bright green above, pale beneath, entire, occasionally emarginate, not in fascicles.

    Although the two plants just noted differ so far as the leaf is concerned in some particulars from the Wellington plant, such differences are probably

    [Footnote] * The Manual description reads, “quite entire,” but even Kirk's type specimens show some leaves not entire.

    Picture icon

    Plate IX
    Leptospermum scoparium Leonard Wilson, growing naturally near Port Levy, Banks Pennsula.

    Picture icon

    Plate X
    Flowering branch of Leptospermum scopanum Leonard Wilson, showing the double white flowers

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    entirely environmental. The most interesting point is the greatly reduced leaves present with much larger ones on the Riwaka plant, and such suggest that perhaps the Trelissick Basin plant is, after all, a reduced form. An examination of flowers and fruit can alone settle this interesting point, but I am still inclined to agree with my opinion as stated above — that the Trelissick plant is one species, and that the Riwaka and other Nelson plants should be united with the Wellington plant either as a polymorphic or an epharmonic group.

    39. Leptospermum scoparium Forst. (forms with double flowers). (Plates IX and X.)

    In New Zealand Plants and their Story, p. 149 (1910), I have called attention to a form of Leptospermum scoparium with double flowers which was discovered by Mr. E. Phillips Turner, F.R.G.S., in the Volcanic Plateau Botanical District.

    A second plant with double flowers was found some four years ago at Torrent Bay, Nelson, by a lady residing at Motueka. This information I received from Messrs. Nairn and Sons, nurserymen, of Christchurch.

    A third plant with double flowers must now be recorded. This was found recently by Mr. Leonard H. Wilson on his property at Port Levy, Banks Peninsula. I am indebted to Mr. J. Young, Curator of the Christ-church Botanical Gardens, for calling my attention to this interesting plant and for supplying the fine photograph (see Plate IX) of the wild plant in its original habitat, the photograph being taken by his son, Mr. James E. Young. Cuttings from the Port Levy plant were struck by Mr. Young, so that there is now a vigorous specimen in the collection of New Zealand plants in the Christchurch Botanical Gardens.

    Since the doubling of flowers is essentially a teratological phenomenon, one cannot look on such a race, capable only of being reproduced artificially from cuttings or layers, as equivalent to a taxonomic variety. I would propose for it the garden name of “Leonard Wilson,” the plant to be known therefore as Leptospermum scoparium Leonard Wilson.

    40. Myrtus Ralphii Hook. f.

    This species was founded by J. D. Hooker on specimens collected by Dr. Ralph near the City of Wellington in the very early days of the province, and on the east coast of the North Island by Colenso, and it was first published in the Flora Novae-Zelandiae in 1853. Later, in the Handbook of the New Zealand Flora, Hooker suggested that it might be a variety of Myrtus bullata Sol. The species was accepted by T. Kirk (Students' Flora, p. 165) and by Cheeseman (Manual, p. 169), both authors agreeing that it is closely allied to M. bullata.

    During the last few years I have had ample opportunity for examining the “species” in the field, and in consequence have come to the conclusion that it is a polymorphic hybrid between M. bullata Sol. and M. obcordata (Raoul) Hook. f.

    My reasons for the above conclusion are (1) that the “species” is never to be found unless both Myrtus bullata and M. obcordata are present, and (2) that the individuals are strongly polymorphic even when growing in close proximity, some closely approaching M. bullata and others M. obcordata, while leaves of the obcordata and bullata types occur frequently on the same individual.

    I do not think a much better example can be found of the often mentioned “series of intermediate forms” connecting two species than is to

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    be seen in the multiplicity of forms assumed by M. Ralphii and connecting M. bullata and M. obcordata. Thus, to those believing that “intermediates” obliterate the distinctions between groups which if not so connected would be species, the only logical course to take would be either to unite all three species of Myrtus under the earliest name, “bullata,” or to uphold M. bullata and M. obcordata, which form the unlike poles of the series, and to treat the intermediates—i.e., M. Ralphii—as unnamed varieties of whichever of the two species they most resembled. For action of this kind the New Zealand and many other floras offer ample precedent; indeed, one or other of the methods suggested above would be the orthodox taxonomic course to pursue. All the same, the most inveterate “lumper” could not bring himself to unite groups so absolutely different as those represented by M. bullata and M. obcordata.

    Some exact details regarding the polymorphy of Myrtus Ralphii may here be given in support of my contention that it is of unfixed hybrid origin.

    On and near the saddle joining the Kaukau Range and Mount Crowsnest, near Wellington City, there is a remarkable scrub-association which owes its presence to excess of wind. In certain places near its outskirts there is abundance of the three species of Myrtus mentioned above growing side by side. Although frequently somewhat stunted in habit, M. bullata can be recognized at a glance; so too, generally, with the individuals of M. obcordata. But on examining the bushes of M. Ralphii it is seen at once that there is no uniformity amongst the individuals, some coming somewhat near to M. bullata in colour, shape, and blistering of leaf, while others are far more of the obcordata type—some, indeed, being almost identical with that species. Thus a hybrid origin is at once suggested, and close examination for and against such a supposition demanded.

    Happily for such an investigation, Myrtus bullata and M. obcordata possess certain well-marked distinguishing characters. Thus, taking the leaves alone, even were the flowers of the two species identical, so different are the leaves that no taxonomist would unite the species. For bullata there is (1) the large leaf, (2) its bullate surface, (3) its usually acute apex, (4) its power of becoming reddish-brown when exposed to the sun, and (5) the base of the lamina not narrowed into the petiole. True, the bullate surface may be strongly flattened in a plant grown in complete shade, but it is always present more or less and is a marked unit-character. Then, for obcordata there is (1) the small leaf, (2) the rounded emarginate apex, (3) the flat surface, (4) the tapering base of the lamina, and (5) the more feeble response to coloration by intense light.

    A number of specimens were collected of the three “species” of myrtle growing side by side on the outskirts of the wind-swept scrub, each specimen being taken from one individual. Of these, after examination, some were put on one side as true Myrtus bullata, others as true M. obcordata, and twenty-two were considered to be M. Ralphii.

    A closer examination of these twenty-two showed that the specimens fell into two classes—the one with large brownish-red, more or less bullate leaves, and the other with much smaller, greener, and flatter leaves. But these differences affected only the bulk of the leaves of each specimen. From even the largest-leaved specimens with leaves of bullata type small leaves of obcordata type were picked. Any of the fundamental characters mentioned above might be present, absent, or even combined. The twenty-two M. Ralphii, specimens were each numbered and examined in detail. Here are a few results:—

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    No. 1 had leaves about 17 mm. long by 15 mm. broad, with reddish slightly bullate surface, the apex subacute, and the lamina-base not tapering —i.e., they were almost pure bullata type. But other leaves were only 10 mm. long by 9 mm. broad, and had the obcordata lamina-base, while one leaf was slightly emarginate.

    No. 4 had many obovate leaves, but others tapered at both apex and base of lamina, and in one case the apex was acute; some were almost flat and some slightly bullate.

    No. 5 had its slightly bullate leaves generally emarginate with tapering lamina-base; some leaves were almost rotund. This specimen might well have been taken for M. obcordata were it not for the slightly bullate leaves.

    No. 7 had leaves up to 19 mm. long by 15 mm. broad, their apex generally rounded or subacute, but the bases of the laminae generally tapered and a few leaves had an emarginate apex.

    No. 8 showed little sign of any obcordata character, but a few leaves had their bases strongly tapering.

    No. 9 was a distinct form with the large (20 mm. by 15 mm.) leaves pale green, but here again actual obcordate leaves were present.

    No. 10 strongly approached M. obcordata, but traces of the bullate surface were present, while in some leaves the emarginate apex was wanting and in many not strongly developed.

    No. 14 was a distinct form with quite small leaves, but these were distinctly of the bullata type, though even here one obcordate leaf was noted.

    No. 16 is specially worthy of mention. It had bright-green flat leaves, small, but larger than in M. obcordata of the locality. There was hardly a trace of emarginate apex, and the base of the lamina did not markedly taper. Here the most characteristic feature of the series of intermediates—the more or less bullate surface—was absent, but so was the emarginate apex of M obcordata.

    No. 17 was similar to No. 16, and were it not for the number of leaves with non-emarginate apex and a very slight trace of a bullate surface here and there the specimen would be M. obcordata pure and simple.

    My contention of the hybrid origin of Myrtus Ralphii does not rest upon the above examples alone. At the “Meeting of the Waters,” near New Plymouth, there, not in a wind-swept habitat, but in the moist, still atmosphere of the forest-interior, I saw an astonishing series of intermediates between M. bullata and M. obcordata, both these species being also present. It was seeing these plants, indeed, which first suggested the theory of hybrid origin, and which led me to carefully examine the plants of the Wellington wind-scrub. Unfortunately, I was not in a position at the time to secure material for a searching examination.

    At Kenepuru Inlet, Marlborough Sounds, I collected specimens of Myrtus Ralphii. At that time I had no suspicion of its hybrid origin, or I should have collected far more copiously and taken special notes. But the specimens did strike me as not typical M. Ralphii. Examining them (five specimens) now I see that most of the leaves are more or less rotund, large, ± 15 mm. long, and have little trace of a bullate surface. But an emarginate apex is present in a good many cases, and occurs on leaves even 10 mm. long. One specimen has much smaller leaves, obcordate or broadly obovate, and it may be true M. obcordata.

    In Colenso's herbarium, now to be consulted at the Dominion Museum, Wellington, there are a number of Hawke's Bay specimens of Myrtus Ralphii. Amongst these there is no uniformity, and they present features such as already described.

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    The distribution of M. Ralphii needs a few words. As Cheeseman has pointed out, it is a local plant and occurs throughout the North Island, Ahipara being the most northerly locality yet recorded. This is the only locality in Mangonui County known to Carse (Trans. N.Z. Inst., vol. 43, p. 210, 1911), but M. obcordata and M. bullata grow in the same locality, which, like M. Ralphii, is according to Carse the only locality for the former. Here is indeed a crucial case. M. bullata is common throughout Mangonui County, according to Carse (a most trustworthy observer); M. obcordata is only known at Ahipara, but this, too is the sole station for M. Ralphii!

    Without going into further details, I think all must agree that a strong case is made out for the hybrid origin of Myrtus Ralphii. How far all the individuals are actually the F1 generation between M. bullata and M. obcordata it is impossible to say, but the extreme polymorphy suggests that F2 and perhaps other generations are present where individuals are abundant. It is also interesting to see how certain characters may appear unchanged (pure), how others are obvious mixtures, and how others are suppressed; but without actual breeding experiments no conclusions can be drawn.

    Taxonomically the only change demanded if M. Ralphii be considered a hybrid is to write the name thus: X M. Ralphii.

    Appendix.

    Since writing the above I have received from Mr. R. H. Rockel, M.A., a representative collection of the myrtles growing in the forest at the “Meeting of the Waters,” near New Plymouth. Each specimen of the sixty-one specimens sent was taken from a different individual, and so great has been the care exercised by Mr. Rockel and a friend of his who assisted in the work that probably nearly every form of the area in question is represented.

    A casual glance at the collection shows that my former word “astonishing” used with regard to the polymorphy of Myrtus Ralphii in that locality is no exaggeration. A more detailed examination of the material shows every gradation between typical Myrtus obcordata and typical M. bullata; there are, in fact, specimens which could be called “giant obcordata” and “dwarf bullata.” There is also a series of specimens which match the figure (No. 94) of M. Ralphii in Kirk's Forest Flora. Though, taken as a whole, the specimens can be arbitrarily divided into a number of groups, the majority of the specimens has each its special characteristics. The following call for particular mention:—

    (1.)

    Leaves stained brown, slightly bullate, apex rounded usually but some with obtuse apex and one or two slightly emarginate, bases rounded or tapering; lamina generally large—e.g., 2.5 cm. by 2.3 cm.

    (2.)

    Leaves similar to those in No. 1 but very pale green in colour.

    (3.)

    Leaves quite of obcordata type so far as size, base, and colour go, but none are obcordate.

    (4.)

    Leaves similar to those of No. 3 but considerably larger, but one or two of the smallest leaves are true obcordata.

    (5.)

    Leaves for the most part very deeply stained with purple, base much tapering, apex rounded or subacute, blistering considerable, lamina frequently about 1.9 cm. by 1.2 cm.

    (6.)

    Many leaves almost rotund but all with emarginate apex, lamina averages about 11 mm. by 11 mm.

    – 183 –
    (7.)

    Most of the leaves large, deeply coloured with purplish-brown, somewhat bullate, and suddenly narrowed into an acute apex, but some of the smaller leaves have a rounded apex.

    (8.)

    Leaves strongly bullate, apex rounded but occasionally emarginate in the smaller leaves, average lamina about 1.7 cm. by 1.5 cm.

    (9.)

    Average lamina only 8 mm. by 6 mm., surface flat, hardly a trace of emarginate apex.

    (10.)

    Leaves tapering both at apex and base, most rather large, flat, one or two rather large obcordate leaves present.

    Comparing the series of specimens just dealt with, on the whole each specimen shows more uniformity than in the Kaukau-Crowsnest series, but this may be due, in part, to the specimens being smaller. There does not seem to be any evidence of a fixed race being present.

    41. Senecio (the coastal species of West Wanganui Inlet, hitherto referred to S. rotundifolius (Forst. f.) Hook. f.

    In Trans. N.Z. Inst., vol. 39, p. 446, 1907, Cheeseman records, without special comment, Senecio rotundifolius as growing at West Wanganui Inlet. Earlier (Manual, p. 383, 1906) the same botanist had referred the shrub common near Cape Foulwind to the same species. More recently Petrie (Trans. N.Z. Inst., vol. 46, p. 30, 1914) has referred, “without hesitation,” the Cape Foulwind plant to Senecio elaeagnifolius Hook. f., stating, “I examined a great many specimens of this shrub [the Cape Foulwind plant], and found that the leaves, though more coriaceous than usual, are nearly always longer than broad, in outline more or less ovate or ovateoblong, and not rarely waved or repandly toothed at the margin. At an elevation of 2,300 ft. or so on the Longwood Range, Southland, specimens of S. elaeagnifolius may be seen in the forest with leaves approaching those of S. rotundifolius much more closely than do any to be found near Cape Foulwind.”

    Recently I have received from Mr. B. C. Aston a living specimen, but not in flower, of the West Wanganui Senecio. This specimen I should certainly hesitate to refer either to S. rotundifolius or to S. elaeagnifolius. For instance, it differs at once from both species in that the branchlets, the very youngest excepted, are covered with a smooth, not grooved, purple bark altogether lacking tomentum but, in part, most minutely pubescent, whereas similar, or indeed older, branchlets of the other two species are densely covered with pale-buff tomentum. Also, the tomentum, of the under-surface of the leaves is rather thin, white and not buff as in S. rotundifolius and S. elaeagnifolius, and puts one in mind of that of Olearia arborescens (Forst. f.) Cockayne and Laing. The youngest branchlets are covered more or less with a white pellicle of hairs, through which the purple bark soon becomes visible. In addition, the shrub, according to Mr. Aston's notes, is only a few feet high, and not almost a tree as is Senecio rotundifolius. But this low stature may be caused by the plant growing on cliffs, the only habitat where it was noted.

    As for shape, none of the leaves are rotund, but obovate and oblong are the commonest forms. The leaf-base is slightly unequal and cuneate, but such a base is shown in specimens of Senecio rotundifolius which I collected at Anita Bay (Fiord Botanical District). The midrib is much keeled, sometimes glabrous or almost so for its entire length, or it may be covered by a thin pellicle of white hairs.

    – 184 –

    From the above it seems clear that the taxonomic position of the West Wanganui Inlet plant is quite uncertain; it may indeed be, as Mr. Aston suggests, an undescribed species. It is certainly not typical Senecio rotundifolius, the northern limit of which appears to be Jackson's Bay, as stated in the Manual. Neither is it typical S. elaeagnifolius. At present it seems best to look upon it as belonging to a group confined to the North-western Botanical District which may be either a distinct species or a variety of either S. elaeagnifolius or S. rotundifolius.

    42. Sophora prostrata Buch.

    Buchanan described Sophora prostrata as a “rigid prostrate rambling shrub 12–18 in. high” (Trans. N.Z. Inst., vol. 16, p. 395, 1884). Kirk and Cheeseman both describe it as prostrate. That it frequently is quite prostrate and but a few centimetres high is true enough, but this extreme degree of depression appears to be due entirely to its environment. The really important characters which distinguish the species from any of the other species of Sophora are its divaricating growth-form, the smaller flowers solitary or in pairs, the standard almost equalling the wings, and the small pod with few seeds. Specimens more than 1.8 m. high, and probably much higher, are common enough, but they never grow out of the divaricating growth-form stage of development. The species reproduces itself true from seed.

    The actual southern limit of Sophora prostrata has not been ascertained, but it does not seem to extend into the North Otago Botanical District, although the conditions there are ideal for its requirements. Personally, I have not seen it on the Canterbury Plain south of the Rakaia River, nor in the mountainous area to the south of the Waimakariri River basin. According to Cheeseman (Manual p. 123), S. prostrata is found in the mountains. But it also occurs in the lowland belt, nor do I think it ascends much above 900 m.

    43. Veronica salicifolia Forst. f. var. angustissima Cockayne var. nov.

    Foliis lineari-lanceolatis, racemis longis gracilibus laxifloris, calycis lobis anguste lanceolatis acutis.

    North Island: Ruahine-Cook Botanical District—Otaki Gorge, base of Tararua Mountains, on more or less stony ground. L. C.

    This variety is distinguished at once from any other described variety of Veronica salicifolia by the following combination of characters: Linearlanceolate thin leaves ± 10 cm. long by ± 10 mm. broad, slender racemes ± 17 cm. long with the flowers rather distant, the rhachis and pedicels most minutely pubescent, the deeply-cut calyx almost as long as the corolla-tube with long narrow lanceolate acute segments, the white corolla, and the far-exserted purple anthers.

    When not in bloom the plant might be easily confused with broad-leaved forms of Veronica angustifolia A. Rich., but from that species it is at once separated by the much longer racemes, the larger calyx, and the narrow acute not obtuse calyx-segments.

    III. Phytogeographic.

    Although the localities given below have for the most part not been recorded hitherto, in this series of papers the station of a species, though already published, if it is not generally known, will in certain cases be

    – 185 –

    given. Another class of species, the distribution of which requires defining with much more detail, includes those mentioned in the Manual as “often local,” “probably not uncommon but easily overlooked,” and similar statements.

    The distribution of varieties needs far greater attention than is usually accorded them. The variety and not the aggregate species being the real entity, until varietal distribution is put on a sounder footing any truly scientific discussion of the distribution in general of the New Zealand flora will not be possible. What are really wanted from the evolutionary and historical standpoints are accurate records both of the distribution of the aggregate species and of the microspecies which compose them; but before such a study is possible many so-called “valid species” must be joined together as aggregates, while many more varieties of the present aggregates must be constituted.

    The crying need of New Zealand floristic botany on the phyto-geographical side is undoubtedly a much more intensive study of distribution. Full lists of species, & c., for unbotanized localities are demanded. The critical points, where two botanical districts join one another, require a most intensive study. These boundaries at present are nearly all highly problematical, even in areas apparently well known. The botanical hunt should not be merely for “something new”: the presence or absence of the commonest species is generally a matter of far greater importance than the finding of a rarity.

    1. Acaena saccaticupula Bitter.

    South Island: North-eastern Botanical District—(1.) Eastern part of Hurunui River basin: A. Wall! (2.) Trelissick Basin, Canterbury, at about 900 m. altitude: A. Wall!

    This species is Acaena adscendens, in part, of the Manual. It is apparently common on the eastern side of the Southern Alps generally, but is not usually found in great abundance in any station. It appears to occur chiefly in wettish ground. Exact information as to its ecological requirements, distribution, and polymorphy is wanted.

    2. Acaena Sanguisorbae Vahl. var. viridior Cockayne.

    South Island: (1.) Sounds Subdistrict of Ruahine – Cook Botanical District — Near the Nelson City waterworks: L. C. (2.) North-eastern Botanical District—In the Kaikoura neighbourhood: A. Wall!

    Most likely this well-marked variety is of wide distribution, but so far it has not been recorded to the north of the neighbourhood of the city of Wellington or to the south of Banks Peninsula.

    3. Angelica geniculata (Forst. f.) Hook. f.

    South Island: Eastern Botanical District—(1.) On rock, Malvern Hills: A. Wall! (2.) On limestone rock at junction of the River Porter and the Broken River, Trelissick Basin: A. Wall!

    This species has now been reported far inland in various parts of New Zealand, and can no longer rank as a special coastal plant.

    4. Apium prostratum Labill. var.

    South Island: Eastern Botanical District — By side of stream on wet bank near Scargill, Canterbury, at about seven miles from the sea. A. Wall and L. C.

    – 186 –

    5. Asperula perpusilla Hook. f.

    North Island: Volcanic Plateau Botanical District—Tall tussock grassland (“grass-steppe” of my Report on a Botanical Survey of the Tongariro National Park), Waimarino Plain. H. Carse.

    6. Asplenium Colensoi Hook. f.

    North Island: Ruahine-Cook Botanical District — Common on moist shady banks near streams in forest of Mount Crowsnest, Wellington. L. C.

    7. Carex dipsacea Berggren.

    North Island: Volcanic Plateau Botanical District—By the roadside, Waimarino. H. Carse.

    8. Carex Solandri Boott.

    North Island: Volcanic Plateau Botanical District—Margin of forest, Waimarino. H. Carse.

    9. Carmichaelia grandiflora Hook. f.

    South Island: Eastern Botanical District—(1.) Mount Torlesse: A. Wall! (2.) Mount Hutt: A. Wall!

    Professor Wall's specimens were too small for me to refer them to the special variety of the species to which they belonged.

    10. Celmisia Armstrongii Petrie.

    South Island: Western Botanical District—Mount Tuhua, in herb-field, subalpine. J. E. Holloway!

    Mount Tuhua is a peak, 1,093 m. high, situated to the east of Lake Kaniare, near Hokitika, and distant from the sea about fifteen miles. Its flora was unknown until the Rev. Dr. Holloway sent me a small collection of plants collected by him mostly above the forest-line. This collection shows the flora to be much the same as that at similar altitudes on the actual Divide.

    11. Celmisia intermedia Petrie.

    South Island: Western Botanical District—Mount Tuhua, in herb-field, subalpine. J. E. Holloway!

    12. Claytonia australasica Hook. f.

    South Island: Western Botanical District — Styx Valley. J. E. Holloway!

    13. Coprosma foetidissima Forst.

    North Island: Ruahine – Cook Botanical District — Near Makerua Railway-station, on sandstone bluff. L. C.

    14. Coprosma serrulata Hook. f.

    South Island: Western Botanical District—Browning's Pass. J. E Holloway!

    – 187 –

    15. Corallospartium crassicaule (Hook. f.) J. B. Armstg.

    South Island: Eastern Botanical District — Mount Hutt, subalpine. A. Wall!

    16. Donatia novae-zelandiae Hook. f.

    South Island: Western Botanical District—Mount Tuhua, subalpine. J. E. Holloway!

    17. Dracophyllum Kirkii Berggren.

    South Island: Western Botanical District — Browning's Pass. J. E. Holloway!

    18. Drapetes villosa (Berggren) Cheesem.

    South Island: Western Botanical District—Mount Tuhua, subalpine. J. E. Holloway!

    19. Epilobium chionanthum Hausskn.

    South Island: Eastern Botanical District — Swamp on Waimakariri River bed, on the Craigieburn Run. A. Wall!

    20. Euphrasia cuneata Forst. f.

    North Island: Ruahine-Cook Botanical District—(1.) Near Plimmerton, in a remarkable subassociation of a Typha-Phormium swamp where Leptocarpus simplex is dominant: L. C. (2.) Waikanae, on Sphagnum: W. H. Field.

    21. Forstera Bidwillii Hook. f.

    South Island: Western Botanical District—Mount Tuhua, subalpine. J. E. Holloway!

    22. Gaultheria perplexa T. Kirk.

    South Island: Eastern Botanical District — Near the Rakaia Gorge. A. Wall!

    23. Gentiana serotina Cockayne.

    South Island: Eastern Botanical District—Hills near “The Point,” Rakaia Gorge. A. Wall!

    24. Gleichenia Cunninghamii Heward.

    South Island: Eastern Botanical District — Forest at base of Mount Hutt. A. Wall!

    The localities previously known for this fern in the Eastern Botanical District are: Mount Peel; Alford Forest; Banks Peninsula, especially near Port Levy (T. H. Potts, Out in the Open, p. 53, 1882).

    25. Isotoma fluviatilis (R. Br.) F. von Muell.

    South Island: (1.) Eastern Botanical District—Shore of Lake Rubicon, Mount Torlesse: A. Wall! (2.) North-eastern Botanical District—Awatere River basin, subalpine: C. E. Foweraker and L. C.

    This species, first recorded for New Zealand in the Manual, p. 401, is now known to occur in all the botanical districts of the South Island excepting the Western and Fiord Districts.

    – 188 –

    26. Lobelia anceps L. f.

    North Island: Ruahine-Cook Botanical District—On drained ground of the Makurerua Swamp, but apparently not common. L. C.

    27. Lycopodium cernuum L.

    South Island: North-western Botanical District—Near Westhaven (West Wanganui). B. C. Aston!

    This discovery of Mr. Aston's is of considerable phytogeographical importance, since it extends the southern range of L. cernuum from the neighbourhood of Lake Taupo (Volcanic Plateau Botanical District) for a distance of about eighty-four miles. It also adds another species to the following remarkable list of plants which occur in the North-western Botanical District, but which otherwise are confined to the Northern Botanical Province or extend only a short distance beyond its southern boundary: Astelia Banksii, Adiantum aethiopicum, Blechnum Fraseri, Dracophyllum latifolium, Schoenus tendo, and Pterostylis puberula.

    28. Lygodium articulatum A. Rich.

    North Island: Volcanic Plateau Botanical District—In forest, Waimarino; apparently rare. H. Carse.

    The Manual gives the Bay of Plenty and Kawhia as the southern limits of this fern. The above record extends its southern range considerably.

    29. Metrosideros lucida (Forst. f.) A. Rich.

    South Island: Eastern Botanical District — In patches of forest in gullies on hills near “The Point,” Rakaia Gorge. A. Wall!

    30. Myosotis Townsoni Cheesem.

    South Island: Western Botanical District — Browning's Pass. J. E. Holloway!

    This well – marked species has hitherto been recorded only from the Brunner Range and Lyell Mountains, in the North-western Botanical District; its known range is thus extended about sixty miles to the south.

    31. Notospartium torulosum T. Kirk.

    South Island: Eastern Botanical District—In the vicinity of the Rakaia Gorge. A. Wall!

    I have only a mere scrap, but it seems identical with Kirk's type. The species has now been recorded from the above locality, from Mount Peel (where it was recently rediscovered by Mr. R. M. Laing, B.Sc.), the Waikari Hills, the Hanmer Plains area, and the vicinity of the River Mason. Mr. D. Petrie, M.A., suggested to me some time ago that the Clarence Valley plant discovered by Mr. Aston was possibly neither the above nor Notospartium Carmichaeliae; and he may quite well be right, as its much-swollen pod looks very distinct.

    32. Olearia Colensoi Hook. f.

    South Island: Western Botanical District — Mount Tuhua; an important member of the subalpine scrub. J. E. Holloway!

    – 189 –

    33. Ourisia macrocarpa Hook. var. calycina (Col.) Cockayne.

    South Island: Western Botanical District—Mount Tuhua, in herb-field. J. E. Holloway!

    This variety has been recorded by Mr. D. L. Poppelwell from as far south as the mountains near the Haast Pass, but its exact southern limit—i.e., where it is replaced by var. cordata (the type of the species)—is not yet known.

    34. Plagianthus cymosus T. Kirk.

    South Island: South Otago Botanical District—Banks of Waihopai Stream, near Invercargill. J. Crosby Smith!

    As Mr. Crosby Smith's record of this interesting plant in his list of Southland plants (Trans. N.Z. Inst., vol. 46, p. 223, 1914) may be easily overlooked, I am calling attention to this station.

    35. Pseudopanax lineare (Hook. f.) C. Koch.

    South Island: Western Botanical District—In subalpine scrub of Mount Tuhua. J. E. Holloway!

    36. Ranunculus chordorhizos Hook. f.

    South Island: Eastern Botanical District—Mount Hutt, on subalpine shingle-slip. A. Wall!

    37. Ranunculus Enysii T. Kirk.

    South Island: Eastern Botanical District—Mount St. Bernard. H. Wall! R. Enysii, according to the Manual, is said to occur not only in the Waimakariri River basin, but also, without there being any stations intermediate, on the East Taieri Hills (South Otago Botanical District) and near Lake Harris (Fiord Botanical District). The Taieri station is given on the authority of Buchanan, his Ranunculus tenuis from that locality being considered by Cheeseman as a form of R. Enysii with the leaves more pinnately divided than usual. But R. tenuis Buch. includes not only the Taieri plant but one from Masterton (Ruahine-Cook Botanical District), while the figure (Trans. N.Z. Inst., vol. 20, pl. xii, 1888) does not match any form of R. Enysii from its original habitat; therefore I think the Taieri habitat should not be accepted. I would also exclude the Lake Harris and Masterton (probably Tararua Mountains) habitats. Should it eventually be proved that I am right, then the species under consideration is, on our present knowledge, confined to the Waimakariri River basin and to the south-eastern portion of the Hurunui River basin, where Professor Wall recently collected it.

    Two very distinct forms of the species were collected by Wall on Mount St. Bernard, and I have also in my herbarium and garden several well-marked forms, but I await cultivation tests before going into the matter of varieties in this rather puzzling aggregate species.

    J. B. Armstrong (Trans. N.Z. Inst., vol. 12, p. 336, 1880) includes Ranunculus geraniifolius Hook. f. in his catalogue of the plants of Canterbury, but is seems almost certain that the plant he had in mind was R. Enysii, to which R. geraniifolius bears no small resemblance.

    – 190 –

    38. Ranunculus insignis Hook. f.

    North Island: Volcanic Plateau Botanical District—Mount Ngauruhoe, on wet lava cliffs. H. Carse.

    This species is not mentioned in my Report on a Botanical Survey of the Tongariro National Park, but it has since been noted by Mr. Allison, of Wanganui, on the south-eastern side of Ruapehu; by Mr. E. Phillips Turner in the bed of the Maungaturuturu River; and by Mr. Carse as above. All the same, it appears to be an uncommon plant for the central group of volcanoes in general and the adjacent part of the Volcanic Plateau.

    39. Raoulia glabra Hook. f.

    North Island: Ruahine-Cook Botanical District—On summit and other stony exposed places on the Kaukau Range. L. C.

    In Aston's catalogue of Wellington plants (Trans. N.Z. Inst., vol. 43, p. 235, 1911) the only localities given for R. glabra are the Rimutaka and Tararua Mountains.

    40. Rubus parvus Buchanan.

    South Island: Western Botanical District—Styx and Arahura Valleys. J. E. Holloway!

    In the Manual the Taramakau Valley is given as the southern limit of Rubus parvus. It is, however, now known to extend almost to the Fox Glacier, and probably it extends still farther to the south. It appears, indeed, to be fairly common on old river-bed, though perhaps somewhat local, throughout the North-western and Western Botanical Districts. Poppelwell does not record its occurrence in the neighbourhood of the Haast Pass or the River Haast.

    41. Scirpus inundatus Poir. var.

    North Island: Volcanic Plateau — Wet ground on Waimarino Plain. H. Carse.

    42. Selliera radicans Cav.

    South Island: Eastern Botanical District—(1.) Near the junction of the Porter River and the Broken River, Trelissick Basin: A. Wall! (2.) On the shores of certain of the small lakes (Marymere, & c.) and the slopes adjacent, near Mount St. Bernard: A. Wall!

    The Manual gives only quite general information regarding the inland distribution of this extremely common coastal plant. Aston (loc. cit., p. 236) states that it ascends to 3,500 ft. on the Kaimanawa Mountains. Petrie records it (Trans. N.Z. Inst., vol. 28, p. 565, 1896) as “rare inland [Otago] and much reduced in size, as at Lakes Wanaka and Te Anau. Ascends to 1,000 ft.”; and the Manual, p. 395, “ascending to over 2,500 ft. at the base of Ruapehu.” Wall's specimens agree with Petrie's remarks as to reduction in size.

    43. Urtica ferox Forst. f.

    North Island: Volcanic Plateau Botanical District—On bank of river, Makatote Gorge. H. Carse.

    – 191 –

    44. Urtica linearifolia (Hook. f.) Cockayne.

    North Island: Ruahine-Cook Botanical District — Makurerua Swamp, where drained, climbing over shrubs. L. C.

    45. Veronica amplexicaulis J. B. Armstg.

    South Island: Eastern Botanical District — Mount Peel, subalpine. H. H. Allan!

    Previously I have only known this species from the cultivated plants in the Christchurch Botanical Gardens, which were probably cuttings from the original plant. Also, in the Manual Armstrong's original habitat, “Upper Rangitata,” is the only one given. Mr. Allan's specimens have not yet bloomed in my garden, but they seem to match exactly the not-readily-mistaken vegetative form of V. amplexicaulis, of which I have also a cultivated example.

    46. Veronica Haastii Hook. f. var. macrocalyx (J. B. Armstg.) Cheesem.

    South Island: Western Botanical District—Browning's Pass neighbourhood. J. E. Holloway!

    I am inclined to think it would be better to treat this variety as a species. If not, then V. epacridea should also be united to V. Haastii. The plant in question has so far been recorded only from Mount Rolleston, the vicinity of the Waimakariri glaciers, the Rangitata Valley, and the above locality.

    Art. XVIII.—A Note on the Young Stages of Astraea heliotropium (Martyn).

    [Read before the Wellington Philosophical Society, 12th December, 1917; received by Editors, 31st December, 1917; issued separately, 30th May, 1918.]

    In his “A Commentary on Suter's Manual of the New Zealand Mollusca* Iredale makes the following statement on page 444: “My disposition of the species ranked by Suter in the families Liotiidae, Vitrinellidae, and Cyclostrematidae are as follows: “Transfer Liotia serrata Suter, 1908, and Liotia solitaria Suter, 1908, to the genus Angaria Bolten, 1798, in the family Trochidae,” & c.; and on page 439 of the same volume, speaking of the genus Angaria Bolten, he says, “This genus has not yet been recorded from New Zealand, though I have recorded two species at the Kermadec Islands…. The two species, Liotia serrata Suter, 1908, and Liotia solitaria Suter, 1908, are probably both juveniles of this genus: the latter certainly is, whilst the species Suter compared it with—viz., L. stellaris Ad. & Rve.—is also a juvenile Angaria, as is shown here in the British Museum, the type being so placed when it was described.”

    I have a number of specimens dredged by Captain Bollons from various localities which show very clearly that Iredale was mistaken in transferring

    [Footnote] * Trans. N.Z. Inst., vol. 47, p. 417–508, 1915.

    – 192 –

    Liotia solitaria Suter to the Trochidae, as it is undoubtedly a juvenile Turbinidae, belonging to the genus Astraea Bolten, 1798—it being, in fact, the juvenile of Astraea heliotropium (Martyn).

    In the Manual of the New Zealand Mollusca, 1914, Suter records Astraea heliotropium (Martyn) as occurring from the Bay of Islands to Stewart Island—that is, practically all round the New Zealand coast. It has been obtained alive in Wellington Harbour, and is plentiful at Kapiti Island. From a dredging off Cuvier Island in 38 fathoms I obtained two specimens, of which Mr. Suter says, “No doubt the embryonic shells of Astraea heliotropium (Martyn). Identical with my unfortunate Liotia solitaria.” From near the Hen and Chicken Islands, in the Hauraki Gulf, in about 30 fathoms, a minute specimen, of 0.5 mm., without spines, was obtained, which Mr. Hedley said was the embyro of an Astraea, and it is identical with the protoconchs of the Cuvier Island specimens. Then, from off Channel Island, in Hauraki Gulf, 26 fathoms, five specimens were obtained, measuring 1.5 mm., 2. mm., 2.5 mm., 3 mm., and 4 mm. diameter — all specifically identical with the Cuvier Island specimens. On the last spine of the largest specimen the adult sculpture of Astraea heliotropium is just beginning to show. Unfortunately, it is rather damaged and water-worn.

    A dredging off Chetwode Island, Cook Strait, 55 fathoms, gave two young Astraea heliotropium (Martyn), of 18 mm. and 19 mm. diameter, so far developed as to be quite unmistakable; and two smaller ones, of 5 mm. and 3.5 mm., the larger of which is much broken, though enough remains to identify it with the larger ones, while it at the same time shows most clearly its specific identity with the smallest, which is specifically identical with the northern specimens. The smallest (3.5 mm.) has only three whorls, and a wide umbilicus, within which all the whorls are clearly visible. The upper surface is very slightly concave, the whorls coiled almost in one plane; colour white, the interior of the lip slightly nacreous. The largest specimen has the protoconch sufficiently distinct to establish the specific identity of the smallest.

    Mr. J. C. Andersen collected three young specimens of Astraea heliotropium (Martyn) on the beach of Kapiti Island—good examples, 30 mm., 34 mm., and 40 mm. In all three the protoconch is unusually clean, and under a powerful pocket-lens the embryonic shell is clearly visible; while the largest one is particularly useful as exhibiting the gradual development of the spines, the change from the depressed discoidal spire of the juvenile to the somewhat raised spire of the adult, and the gradual increase of the at-first nodulous spiral ribs, which when the shell reaches a diameter of about 25 mm. change to close sharp growth lamellae on the spirals. These three specimens are in the reference collection in the Dominion Museum, Wellington.

    From dredgings in Dusky Sound I have a series of seven, of which four are quite minute and the other three are unmistakable young Astraea heliotropium (Martyn), 20 mm., 19 mm., and 13 mm. diameter, with clean spires which show the embryos very well. This is perhaps the best locality for this species.

    If all these specimens were mixed together it would be an absolute impossibility to be sure of the locality of any single specimen. Specimens illustrating this change from juvenile to adult have been placed in the Dominion Museum.

    – 193 –

    Art. XIX.—On Mosquito Larvicides.

    [Read before the Wellington Philosophical Society, 25th July, 1917; received by Editors, 31st December, 1917; issued separately, 10th June, 1918.]

    In connection with work that has been entrusted to me in some of the military camps in the matter of fly-control it has been necessary to investigate the effectiveness of various substances as killing agents. Incidentally, the matter of larvicides for mosquitoes came under investigation. This year the New Zealand Institute has set aside a sum of £25 from the Government research grant, which sum may be drawn upon in refund of actual expenses in investigating and experimenting in this direction. The present paper deals mainly with the relative value of certain mosquito larvicides. The experiments have been made mainly with the larvae of various species of Culex found in New Zealand and with the larvae of a culicine mosquito found often in brackish water on the coast near Wellington. As there is probably a real danger that Anopheles or other harmful forms may at any time be introduced into New Zealand, it is advisable that methods of extermination should be as effective as possible. I hope to be able shortly to make some contribution to our knowledge of the best means of dealing with adult mosquitoes.

    The work that has been done in the Panama Canal zone under Gorgas, at Khartoum under Balfour, and in other places where disease-bearing mosquitoes occur is well known. Larvae are generally dealt with by means of a film that prevents their breathing when they come to the surface, or by use of a lethal agent that diffuses evenly throughout the water. The substance used as a film is generally crude petroleum. One of the best-known direct lethal agents is an emulsion of crude carbolic acid.

    In Notes on Fly-control in Military Camps, issued last year by the Defence Department, I called attention to the value of light oil* as a killing agent. It is sprayed in mixture or in emulsion with 3 or 4 parts of water, and is very fatal to maggots and to adult flies. It has to be applied in greater strength to kill fly-pupae. Experiments with light oil as a mosquito larvicide show that it is a most valuable substance, whether used as a film or as an emulsion.

    The question whether it is best to use a film or an emulsion depends upon several considerations. Of these, the relation of volume of water to surface may be important. This is, however, a consideration of economy or of ease of treatment. A consideration of actual efficiency is the exposure of the surface to wind. If a surface is wind-swept a film is broken very quickly. Certain experiments in toughening the films will be referred to later. In certain cases it may be best to use both film and emulsion, especially if many pupae are present, these being less easily killed by the emulsion than are the younger larvae.

    Light oil makes a film that spreads more rapidly than crude petroleum; its colour enables the operator to see at a glance whether the film is complete: it is very fatal to insects, and a larva thrusting the breathing-siphon

    [Footnote] * “Light oil” is the lowest of the three great fractions into which the distillation products of coal-tar are first broken, and it comprises those constituents that have a boiling-point up to about 200° or 210° C. The two higher fractions are known as “medium oil” and “heavy oil” respectively.

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    into the film is paralysed and seldom comes again to the surface. Dishes of equal size, 2 ft. by 1 ft. 3 in., containing the same quantity of water and the same number of larvae at the same stage, have been treated, one with light oil, the other with crude petroleum in like amount. In all experiments—and I have repeated them over a dozen times—the larvae under the film of light oil have been dead or helpless on the bottom within fifteen minutes, while in the petroleum dish some have been active after an hour or more. In view of the possible breaking of films, comparative rapidity of action is a matter of great importance. The experiments referred to have been repeated on the large scale on pools in various parts of the North Island, and the laboratory results have been amply confirmed.

    The film is best produced by spraying the pool, but the oil may be sprinkled from a bottle or other vessel, or a leafy twig may be dipped in it and shaken over the water. In choosing a spraying instrument for light oil it is necessary to choose one without rubber tubing, as some constituents of light oil are solvents of rubber.

    Experiments with regard to the toughening of films to render them less easily broken are now being made. Up to the present I have found nothing better than raw linseed-oil. It should be shaken up well with the light oil before being applied. I am not yet sure that the advantage gained is sufficient to justify a strong advocacy of its use; but it certainly does make a film more resistant.

    In testing the killing-power of crude carbolic acid I have taken the formula for the emulsion from the report of the Wellcome Laboratory at Khartoum for 1911, p. 109, where directions sent from Panama are quoted: “Crude carbolic acid* containing about 15 per cent. phenol is heated to 212° F., finely pulverized resin is added, and the mixture kept boiling until the resin is all dissolved. Caustic soda is then added, and the mixture kept at 212° F., for about ten minutes, or until a perfectly dark emulsion without sediment is obtained. The mixture is thoroughly stirred from the time the resin is added until the end.” It is stated that 1 part of this mixture in 5,000 parts of water containing mosquito-larvae will kill all the larvae within five minutes. If it is used in the proportion of 1 to 8,000 the larvae are killed in thirty minutes. In my experiments I was unable to obtain results as good as these. I obtained, however, much better results when using an emulsion of light oil.

    The experiments tabulated below are only a few of a very long series, and all have been verified by actual work at normally infested pools in the open. With regard to various entries in the table I may make the following explanation:—

    In the column headed “Twitching” is noted the time at which the larvae were first observed to be all motionless or twitching helplessly at the bottom of the vessel. This is for all practical purposes the time of death, as the larvae do not recover from this condition unless removed to fresh water. Time of actual death is, however, of importance in view of the fact that mosquitoes sometimes breed in slowly flowing water.

    In the column “Apparently dead” is entered the time at which response could not be obtained to weak induction shocks.

    [Footnote] * A fine account of the efficacy of crude carbolic acid and other larvicides is given by Howard, Dyar, and Knab in The Mosquitoes of North and Central America and the West Indies, vol. i, pp. 379 et seq., Carnegie Inst., Washington, 1912.

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    In the column “Dead” is noted the time at which removal to abundant fresh water was made in cases where this removal did not bring about at least temporary recovery. For this purpose I regarded proof of death as sufficient if no movement of any kind took place within twenty-four hours. No very young larvae were used in these experiments.

    [The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

    Larvae observed to be
    Emulsion. Strength. Number of Larvae. Time. Active. Twitching. Apparently Dead. Dead. Remarks.
    Carbolic ¼,000 3 5 p.m. 6 p.m. 7.30 p.m. 9 p.m. Recover in fresh water.
    " ⅛,000 3 6.25 p.m. 7.25 p.m. 11.30 p.m. "
    " 1/16,000 3 6.30 p.m. 3 days later 4 days later One recovers in fresh water.
    Cresolia ¼,000 3 3.40 p.m. 4.20 p.m. 4.20 p.m. Dead in 40 minutes.
    " ⅛,000 2 3.50 p.m. 4.30 p.m. 6.20 p.m. 6.20 p.m. Dead in 2 hours 30 minutes.
    Light oil ¼,000 * 2 4.50 p.m. 4.52 p.m. 4.52 p.m. Dead in 2 minutes.
    " ⅛,000 6 3.15 p.m. 3.22 p.m. 3.55 p.m. 3.55 p.m. Dead in 40 minutes.
    " 1/16,000 * 6 2.50 p.m. 2.52 p.m. 3 p.m. 7 p.m. 7 p.m. No observation between 3 p.m. and 7 p.m. Dead within 4 hours 10 minutes.
    " ⅓2,000 6 2.50 p.m. 3 p.m. 7 p.m. 2 p.m. next day No observation between 7 p.m. and 2.52 p.m. next day. Dead within 24 hrs.

    Many other substances, including well-known disinfectants and plantsprays, were used, but with no results worth publishing. Sulphates of iron and of copper, potassium ferrocyanide, and other well-known substances gave, in the dilution of 1 in 4,000, negligible results.

    From the above table it will be seen that when there is no access of fresh water an emulsion of light oil may be used in the proportion of 1 in 32,000. The emulsion that will give this result must, of course, be one that contains nearly all the light oil that the emulsionizing agent can carry and that has no needless water. The formulae here given, chosen from a number that have been arrived at, may be relied upon:—

    (1.) Soft-soap 100 parts.
    Light oil 440 "
    Water 100 "
    Caustic soda 80 "

    It is best to add the light oil after the other substances have been heated together to a temperature of 100° C.

    This is a thick jelly, and may be diluted with water to liquefy it.

    (2.) Soft-soap 20 parts.
    Light oil 50 "

    A thick jelly-like soap.

    Where transport was not an important consideration the desired amount of water to make these emulsions liquid would usually be added when they were being made.

    (3.) Castor-oil 50 parts.
    Caustic soda (sat. solution of 98 per cent. caustic soda) 15 "
    Water 20 "
    Light oil 170 "

    [Footnote] * One of these was a pupa.

    [Footnote] * One of these was a pupa.

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    It is best first to make a soap by boiling the castor-oil and the causticsoda solution. When an even yellow-green soap is formed the light oil may be added. Constant stirring is, of course, necessary whichever formula is used.

    As is well known, potash is generally more suitable than soda, but its greater cost makes it unsuitable for this purpose. Owing to a shortage of potash, soft-soap is becoming costly, and therefore other emulsionizing agents are being experimented with. Up to the present good results have been got with resin, neatsfoot-oil and whale-oil. The last-named is the cheapest, and will be used for work in military camps. Unfortunately, it is sometimes difficult to saponify it by the means always available.

    The castor-oil emulsion referred to above is a clear liquid emulsion, and keeps well.

    Art. XX.—On the Age of the Waikouaiti Sandstone, Otago, New Zealand.

    [Received by Editors, 31st December, 1917; issued separately, 10th June, 1918.]

    Although contradictory opinions were held by Hutton and Haast on the one hand, and Cox, McKay, and Hector on the other, as to the relative age and relationships of the Notocene rocks of the north and south sides of the Shag River, all these geologists were in agreement in correlating the Waikouaiti sandstone on the one hand with the Caversham sandstone, and on the other with the Ototara limestone. Both these correlations were accepted also by Park (1910); but it is necessary to remember that at that time he placed the Ototara stone as the uppermost member of the Oamaruian. Marshall, in 1906, did not attempt a more detailed correlation than that the Caversham sandstone belonged to the Oamaru system, but in 1916 he referred to the foraminiferal limestone at Sandymount, which he had previously correlated with the Caversham sandstone, as a representative of the younger limestone of New Zealand—i.e., Ototaran. Thus practically all geologists who have written on the subject have agreed that the Caversham sandstone and Waikouaiti sandstone are the same horizon and are Ototaran.

    The rightness or wrongness of this conclusion has more than a merely local interest, for on it hang two other questions of a more general nature. First, the age of the Dunedin volcanic series can only be limited as regarding its commencement by reference to the Caversham sandstone—until a detailed palaeobotanical investigation of the intervening Fraser's Gully plant-beds is available. Secondly, the Miocene age of the Oamaruian is based very largely upon Chapman's conclusions regarding the Foraminifera collected by Park from the clays underlying the Waikouaiti sandstone, and if the latter is Ototaran the clays are lower Ototaran, or more probably Waiarekan, and the Middle, or more probably Lower Oamaruian, is Miocene. Opinions to the contrary, however, have recently been independently expressed by Marshall and myself (1917). Discussing the Hampden beds, I stated that “the percentage of Recent species in the Waiarekan is not inconsistent with an older age than Miocene for this stage,” while Marshall concluded that “these Onekakara [i.e., Hampden] beds seem to be more rightly classed with the Eocene than with any other European system.”

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    Obviously, then, if Chapman's correlation of the clays of Waikouaiti with the Miocene is admitted, either (a) the lower Ototaran or Waiarekan is Miocene, and the opinions stated by Marshall and myself err in ascribing too great an age to the Waiarekan, or (b) the Waikouaiti sandstone is not Ototaran.

    During a visit to Waikouaiti at Easter, 1917, in company with Professors J. Park and W. N. Benson, of Otago University, I collected from the Waikouaiti sandstone at the North Head a number of brachiopods, of which seventeen were referable to Pachymagas abnormis Thomson, while the remaining three belonged to a small species of Pachymagas with mesothyrid foramen, probably nearly related to the more orbicular forms of P. parki which occur in the Hutchinsonian of All Day Bay.

    Pachymagas abnormis was one of the species which I adduced in 1917 as evidence of the Upper Oamaruian age of the beds in the Takaka Valley, and subsequent discoveries have not invalidated its usefulness in this respect. I have since collected it in the uppermost bed of the Mount Brown limestone at the foot of the dip slope of the cuesta opposite Weka Pass — i.e., at a slightly higher horizon than the holotype, but still probably Hutchinsonian — and a single specimen in the Hutchinsonian greensands of All Day Bay. It occurs abundantly in the Awamoan mudstones of All Day Bay, and thus ranges in the Oamaru district from Hutchinsonian to Awamoan, but has not been found in the Ototaran. Now, a larger number of species are known from the Ototaran of the Oamaru district than from any other stage in any locality in New Zealand, so we are quite justified on the present evidence in considering P. abnormis a purely Upper Oamaruian species.

    Mr. S. S. Buckman, of Thame, England, has suggested in correspondence that Pachymagas abnormis should not be referred to Pachymagas, but should be made the type of a new genus on account of its beak characters, and if this course is followed it would be possible to differentiate a number of species within the somewhat variable series I have referred to P. abnormis. The specimens from the Awamoan mudstones of All Day Bay and from the Waikouaiti sandstone would, however, still have to be retained in the same species.

    The conclusion to be drawn from the presence of this brachiopod, then, is that the Waikouaiti sandstone is not Ototaran (i.e., Middle Oamaruian), but Upper Oamaruian, and it may well be Awamoan, and the underlying clays Hutchinsonian. In this connection an examination of the brachiopods from the sandstone at Seacliff, and from the Caversham sandstone and the greensands underlying the latter rock at the back of Flagstaff, would be of considerable interest, and I should be glad to receive specimens from these localities.

    List OF Papers Cited.

    Marshall,P., 1906. The Geology of Dunedin (New Zealand), Quart: Journ. Geol. Soe., vol. 62, pp. 381–424(ref. to pp. 389–90).

    Marshall,P., 1916. The Younger Limestones of New Zealand, Trans. N.Z. Inst., vol 48, pp. 87–99 (ref. to p. 93).

    Marshall,P., 1917. Fossils and Age of the Hampden (Onekakara) Beds, Trans. N.Z. Inst., vol. 49, pp. 463–66 (ref. to p. 465).

    Pabk, J., 1904. On the Geology of North Head, Waikouaiti, and its Relation to the Geological History of New Zealand, Trans. N.Z. Inst., vol. 36, pp. 418–30.

    Park, J., 1910, The Geology of New Zealand, Christchurch (ref. to p. 139).

    Thomson, J. A., 1917. Diastrophic and other Considerations in Classification and Correlation, and the Existence of Minor Diastrophic Districts in the Notocene, Trans. N.Z. Inst., vol. 49, pp. 397–413 (ref to pp. 409–10).

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    Art. XXI.—On the Distribution of Senecio saxifragoides Hook. f.′ and its Relation to Senecio lagopus Raoul.

    [Read before the Philosophical Institute of Canterbury, 5th December, 1917; received by Editors, 31st December, 1917; issued separately, 10th June, 1918.

    Plates XIXIII.

    1. Introduction.
    (a.) General.

    The problem to be attacked in this paper is suggested in the following passage from L. Cockayne (“Notes on the Plant Covering of Kennedy's Bush, and other Scenic Reserves of the Port Hills,” Report on Scenery Preservation, Parliamentary Paper C.-6, 1915) concerning S. saxifragoides: “It also is a most striking plant. Now, an almost identical species, named Senecio lagopus, also occurs on the main mass of Banks Peninsula, which differs from S. saxifragoides merely in the possession of numerous bristles on the leaf, whereas in the latter such are absent. Yet, so far as is known, S, lagopus does not occur on the Port Hills, nor S. saxifragoides on Banks Peninsula proper. If this is truly a fact, the distribution of these two species, each equally well suited to the rock-conditions of the area, is one of the most remarkable cases of plant-distribution in the world.”

    The same authority, in his description of his new species, Senecio southlandicus (Trans. N.Z. Inst., vol. 47, p. 118, 1915), further says, “The species is, indeed, far more distinct from S. bellidioides and S. lagopus than are these from one another. The classification of the whole series, including those already mentioned, together with S. saxifragoides Hook. f. and S. Haastii Hook. f., is in a most unsatisfactory position. Specimens are constantly coming to me from various correspondents which it is impossible to place with any degree of satisfaction. There are undoubtedly a number of well-marked forms, which demand, at the least, varietal names. Even one fixed character may serve quite well as a specific mark. This is illustrated in the case of S. saxifragoides and S. lagopus (the type from Akaroa), where the presence of numerous bristles, or their absence, on the upper surface of the leaf is the sole distinguishing character, so that, so far' as large plants of the two are concerned, if this character were not present no one could consider them in any degree different.”

    In this paper attention has been directed to these two species solely as they occur on Banks Peninsula.

    Banks Peninsula is situated in lat. 43° 32′ S. and long. 175° 30′ E., and forms a rough elliptical salient on the east coast of the South Island of New Zealand. Its diameter in a N.W.—S.E. direction is about twenty-five miles, and its breadth at right angles thereto about eighteen miles. Some forty miles to the westward stretches the main chain of the Southern Alps, from which the peninsula is separated by the gently inclined expanse of the Canterbury Plains, so that it is almost as completely isolated as regards the distribution of subalpine vegetation as if it had been separated from the mountain region by the sea.

    The oldest rocks within its limits consist of Trias-Jura sedimentaries overlain in places by a thin veneer of Cretaceous rhyolites, but the main

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    Plate XI
    Photographic reproduction of relief map of Banks Peninsula, from original in Canterbury Museum by S. C. Farr.

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    mass of the peninsula was built up in mid-Tertiary times by flows of basalt and fragmentary material of similar lithological character, poured out from two vents situated somewhere near the centres of Akaroa and Lyttelton Harbours. A third focus of activity lay near Mount Herbert (3,012 ft.), but it was of less importance, although it was responsible for the formation of the highest peak in the area. The high cones thus formed were subject to paroxysmal explosions of moderate intensity, and their surface was modified by the establishment on their outer slopes of a well-developed system of radiating valleys. Volcanic action ceased in all probability long before the end of the Tertiary era. After the stream-system had reached a mature stage the land sank, and the sea entered the floors of the enlarged craters and extended a considerable distance up the lower reaches of the valleys, and these now form marked indentations of the coast-line. Owing to the prolonged weathering the land is now covered with a rich and fertile soil, and steep rock-faces occur only on the coast and at higher levels, where the more resistant basalts form at times precipitous cliffs—the' characteristic habitat of the senecios under consideration.

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    Map of Banks Peninsula and Port Hills, showing distribution of the two species of Senecio. L, Senecio lagopus; S, Senecio saxifragoides A, rhyolite escarpment where S. lagopus occurs; B, rhyolite escarpment where neither species occurs.

    The following are the most important geological considerations affecting the distribution and ecological conditions of plants established in the locality:—

    (1.)

    The isolation of the region from neighbouring mountain areas since it was first formed.

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    (2.)

    The uniformity of the lavas which form the majority of rocks in the area. No anomalies of distribution can be interpreted in the light of lithological differences in these rocks.

    (3.)

    As a result of prolonged denudation the crater-ring of the Lyttelton volcano has been broken down at its south-western side and a sector completely removed, so that a stretch of comparatively low country, nowhere over 875 ft. in height, and consisting of exposed rhyolites and sedimentaries, separates the northern part of the crater-ring from the other part of the peninsula. This northern part forms the low range usually called the “Port Hills,” and is referred to throughout this paper, as the habitat of Senecio saxifragoides, by this name.

    For a fuller account of the geological features of this area see J. von Haast, Geology of Canterbury and Westland, 1879, and R. Speight, “The Geology of Banks Peninsula” (Trans. N.Z. Inst., vol. 49, pp. 365–92, 1917).

    (b.) Historical.

    Senecio saxifragoides was first described by Hooker in 1853 (Flora Novae-Zelandiae, vol. 1, p. 144), and in the Handbook its discovery is accredited to Lyall (Handbook, p. 159).

    Hooker, Kirk (Students' Flora, p. 339), and Cheeseman (Manual, p. 372) agree in describing S. saxifragoides as distinguished from S. lagopus only in respect of the leaf, which is described as “clothed with shining silky and woolly hair “(Hooker), “silky or villous” (Kirk), “silky or villous” (Cheeseman), upon the upper surface only, and wanting the stout bristle which characterizes S. lagopus and S. bellidioides. Kirk says, “The leaves are often glabrous or glabrate on the upper surface, but never bristly as in S. lagopus.” Cheeseman says, “A handsome species, separated from large states of S. lagopus, some of which approach it very closely, by the much stouter habit, more copious villous hairs, and larger thicker leaves, which are silky above and never show the stout bristly hairs so characteristic of S. lagopus and S. bellidioides.”

    All agree that these three species, S. lagopus, S. bellidioides, and S. saxifragoides, are very closely allied. Hooker (Handbook) says, “This [S. lagopus] and the two following [i.e., S. bellidioides and S. saxifragoides], though most dissimilar in their usual states, appear to me to be united by intermediate forms,” and (Flora Novae-Zelandiae), “This and the two following are closely allied and very singular species.”

    The distribution of S. saxifragoides is given by Hooker as “Port Cooper”; by Kirk as “Port Lyttelton, Banks Peninsula”; and by Cheeseman as “Port Lyttelton and other localities on Banks Peninsula.”

    All agree in describing the leaf of S. saxifragoides as broader or more nearly orbicular than that of S. lagopus; but they do not quite agree as to the relative size. Hooker makes the leaf of S. lagopus 2 in. to 4 in. long (!); that of S. saxifragoides 3 in. to 5 in. long. Kirk makes the leaf of S. lagopus 1 in. to 8 in. long (excluding the petiole), and that of S. saxifragoides 3 in. to 6 in. long. Cheeseman makes the blade of S. lagopus 1 in. to 5 in. long, and that of S. saxifragoides 3 in. to 6 in. long. Raouls description of S. lagopus (Choix, p. 21) gives the leaf about 1 decimetre (4 in.) long and from 7 to 9 centimetres (3–3 ½in.) broad. Hooker's and Raoul's descriptions would seem to have been based upon comparatively small specimens of both species.

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    The distribution of S. lagopus is given by all authorities as from the Ruahine Mountains to South Canterbury.

    The original description of S. lagopus by Raoul, and his plate (Choix, pl. 17), must here be referred to, as of the greatest importance in the study of the two species. In describing the petiole of S. lagopus, Raoul says, “Petioli … canaliculati in vaginam semiamplexicaulem dense lanatam dilatati “; and in describing the leaf he says, “Folia … pilis rigidis grossis, spinescentibus praesertim ad. margines inspersa.” His plate shows a plant with four large and several small leaves. Of the four large leaves three are glabrate (as the old leaves of both S. lagopus and S. saxifragoides always are): the fourth bears the characteristic “bristles” very thickly close to the margin all round the leaf, or nearly so; and near the apex; less thickly upon the upper third of the leaf or thereabout; the lower part of the leaf bears the hairs only, very thickly distributed. The hairs and bristles occur together over some portions of the leaf, about the middle and towards the apex, but at the apex itself and in its immediate neighbourhood the bristles alone occur. The dual occurrence of hair and bristle* on the same leaf, which no subsequent authority describes at all, will appear to be of great importance to this inquiry; and it may be added that my descriptions of the variant forms of S. saxifragoides given below were fully made before I had seen Raoul's plate.

    The species are further thus referred to by-Laing and Blackwell (Plants of New Zealand, pp. 437–38, 1906): “The handsome S. saxifragoides, sup posed by Kirk to be confined to Banks Peninsula, is undoubtedly the typical S. lagopus of Raoul. It still produces its large-leaved rosettes on the southern faces of cliffs, where Raoul found it, near Akaroa. It is also plentiful behind Lyttelton, often growing in altogether inaccessible localities, and it is the only Senecio which haunts these situations on the Peninsula.”

    2. Special Characters of the Two Species Under Consideration.

    1.

    All round the margin of the leaf of S. lagopus, S. saxifragoides, and S. bellidioides occur at very regular intervals—i.e., at the ends of the veins—rounded glandular protuberances of a very dark red or purple colour. Microscopical examination shows these to be typical hydathodes.

    2.

    The petiole of the leaf of S. lagopus bears quantities of dark-red or purple bristles, generally spotted or pied with white; these are continued up the back of the midrib nearly to the apex of the leaf, and are also present along the margin all round the leaf.

    3.

    S. saxifragoides also shows this purple or pied bristle upon the petiole and the back of the midrib exactly as in S. lagopus, and also bears this bristle all round the margin of the leaf, making a continuous fringe. The young leaves of S. saxifragoides have yellow marginal bristles, which change gradually into purple and continue to deepen in colour up to maturity. The yellow bristle, however, is usually present together with the purple, the yellow being upon the upper surface of the leaf just within the margin, the purple being upon the” margin itself; but they are sometimes more or less mixed together.

    4.

    Forms of Senecio lagopus and Senecio saxifragoides which grow in situations shaded by other vegetation, as among long tussock-grass, or on

    [Footnote] * The term “bristle” is kept throughout, as that employed by previous authorities though the organ is really a glandular hair.

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    the edge of forest, or beneath large plants of Linum monogynum, show a complete or almost complete absence of the purple colouring-matter in the glandular hairs, and also tend to be larger, to have a much longer petiole than usual, and to be less thickly covered with silky hairs or bristles (as the case may be) than the usual form.

    5.

    Though the plant of S. saxifragoides is probably on the average a little larger than that of S. lagopus, the difference is not great. Kirk's measurements do not agree with the others. A leaf of S. lagopus 8 in. long without the petiole would be most exceptional, but leaves 6 in. long with a petiole of from 3in. to 4in. are common—e.g., on Mount Herbert—and S. saxifragoides can hardly ever be much larger than this, though its leaves are generally broader and more substantial. I have a very strong impression, which I hope to verify by future observation, that the plants of S. lagopus in the neighbourhood of Akaroa Harbour are in general distinctly smaller than those of the Mount Sinclair to Mount Herbert area. This would explain the small measurements of Raoul's type. Some of the large individuals of the Mount Herbert area, indeed, almost seem to be intermediate states such as Hooker speaks of. The largest leaf of S. lagopus measured by me shows the following dimensions: Length of blade, 6 in.; length of petiole, 3 in.; breadth of blade, 4 in. This plant grew on the south-western peak of Mount Herbert, and was exceptionally large. Its measurements equal those of S. saxifragoides in any authority and exceed most of them. A most exceptionally large plant of S. saxifragoides, however, gave the following measurements: Length of blade, 7 ½ in.; length of petiole, 4 ⅛ in.; breadth of blade, 6 ¾in. This is much above the average of the species, the plant being shaded by plants of Linum monogynum and tussock-grass.

    6.

    Thus the leaf of typical S. lagopus is found to bear six different types of structure—(a) The thick brownish “wool” of the rootstock, which covers the base of the petiole and seems to pass gradually into (b) long white silky hairs, which clothe the petiole and are continued up into the sinus and on to the lower portion of the leaf; (c) the characteristic stout bristle which occurs, as described below, on the margin and upon the upper part of the blade especially; (d) the dark-red or purple bristle which is thickly intermixed with the white hairs upon the petiole, from the point where the brownish “wool” passes into white hairs up to the apex, or nearly, on the back of the midrib; (e) the glandular marginal purple protuberances; (f) the white tomentum upon the back of the leaf.

    7.

    Many plants of S. lagopus bear the silky hairs as well as the characteristic stout bristles. The silky hairs usually occur very thickly on the petiole and at the base of the leaf and in the immediate vicinity of the midrib; less thickly, if at all, on the rest of the leaf, as depicted in Raoul's plate.

    8.

    Many plants of S. saxifragoides bear the stout bristles which have been hitherto considered to be characteristic of S. lagopus and S. bellidioides. The bristles occur in S. saxifragoides under these conditions:—

    • (a.) They occur near the apex of the leaf upon the upper surface of about one-fourth or one-third of the whole—not near the base, and but rarely on the lower half of the leaf at all (as in Raoul's plate of S. lagopus), though specimens have been observed with the bristles fairly evenly distributed over the whole surface. (See Plate XII.)

    • (b) They occur regularly and as a permanent character all round the margin exactly as in S. lagopus and S. bellidioides.

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    Plate XII
    Young plant of Senecto saxifraffaides, showing bristles, from Mount Pleasant. Port Hills

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    Plate XIII
    Plants of senecio lagopus photographed in ate on Mount Sinclair, Banks Peninsula,

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      (c.) They occur sometimes, not infrequently, near the margin, upon the surface of the leaf, to a distance of about ¼ in. or 1/5 in. from the margin all round the leaf, as in Raoul's plate of S. lagopus.

    • (d.) They occur most frequently upon small, ill-nourished, or depauperated individuals. They occur more frequently upon the lower and outer leaves than upon the upper and inner leaves. Leaves. bearing many bristles have been often found upon plants which are in every other respect typical specimens of S. saxifragoides some whole plants bearing such leaves have been preserved in the collection mentioned below.

      The stout bristles may be almost certainly observed upon all individual plants which are found growing alone, apart from the large masses in which they generally cluster, such plants being generally small and unfavourably situated as regards aspect of soil. Many leaves of such plants have been preserved in the collection, and in many cases the bristles are to be seen as thickly congregated, as evenly distributed, and as stout as in typical examples of S. lagopus and S. bellidioides. Such leaves are, however, all small, much below the average size of the species, but they are from undoubted examples of S. saxifragoides which are seedlings from neighbouring masses of quite normal specimens. A small plant of S. saxifragoides from Mount Pleasant, Port Hills, which is now under cultivation at Canterbury College, has, its leaves thickly and evenly covered with the stout glandular hairs. here mentioned, and is in no respect to be distinguished from specimens of S. lagopus of the same age. (See Plate XIII.)

    • 9. Microscopical examination of the so-called bristle yielded the following results:—

    • (a.) The bristles are simply typical glandular hairs.

    • (b.) The bristles have exactly the same structure in both species.

    • (c.) The bristles upon the margin of each species differ from those of the blade only in the length of the stalk, except that in the case of S. saxifragoides there is a slight difference in colour.

    • (d.) The “silky hairs” of both species have exactly the same structure. The “hair” arises from a single cell, the “bristle” from several.

    • (e.) The glandular organ on the margins of the leaves is a typical hydathode.

    • (f.) The variegated appearance of the bristle is due to the arrangement of the colouring-matter, which is present in some cells, absent in others, with no definite arrangement.

    3. Distribution on Banks Peninsula.

    For the purpose of this study the forms of Senecio lagopus were observed on all the chief peaks on both sides of Akaroa Harbour, such as Brasenose, Stony Bay Peak, Mount Bossu, and Carew Peak; then on the principal high points on the ridge connecting the Akaroa Harbour heights with the main mass of Mount Herbert, such as Mount Sinclair and Mount Fitzgerald. These points are all between about 2,500 ft. and 2,700 ft. high. Both peaks of Mount Herbert, 3,000ft. and 2,800ft. respectively, were visited on several occasions. Specimen leaves of S. lagopus were collected from various points, especially from Mount Herbeit, and preserved.

    The forms of Senecio saxifragoides were next observed, and found to occur on all the peaks of the Port Hills from that south-west of Cooper's

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    Knob to Mount Pleasant, from all of which specimens were collected. These points are mostly from 1,600 ft. to 1,800 ft. high.

    Senecio lagopus was found to occur plentifully in all favourable localities —that is, especially on and about all steep rocks which face south and south-west—practically continuously from the Akaroa Heads, on both sides of Akaroa Harbour, to within a mile of the Port Hills. There is hardly a space of even two miles in extent anywhere along this main line in which S. lagopus does not occur; it occupies an almost continuous line between the points mentioned, and does not here differ generally from the form of S. lagopus as known elsewhere in New Zealand.

    The most rema kable point about this distribution concerns the gap of about four miles, a low undulating neck, which connects the south-west peak of Mount Herbert with the Port Hills. This area is mostly under cultivation, and offers but few escarpments. There are, however; three or four possible localities, rhyolite escarpments or peaks, from 600 ft. to 875 ft. high, chiefly on the northern side of the gap. Upon the highest and most likely of these stations, rocks between Gebbie's and McQueen's Valleys, about 875ft. high, neither has been found; but upon two of them (about 600 ft. to 700 ft. high), one just north of the road from Teddington to Gebbie's Valley and the other just north of that, Senecio lagopus occurs —not plentifully, but undoubted typical S. lagopus. Between these two points and Mount Herbert, a distance of about three miles, neither plant is found, the ground being nearly all under cultivation. The northernmost of these points is barely one mile from the nearest peak of the Port Hills, that south of Cooper's Knob (about 1,600 ft. high), and here S. saxifragoides begins to appear. This seems to me a most striking and puzzling fact. Upon the peak next again to the south (on the Port Hills), though it offers an ideal locality, neither plant occurs.

    We may conjecture that under the original conditions some part of this gap at least was occupied by both species, but at present S. lagopus only is found there, and that only upon the northern side, and upon what is virtually a spur of the Port Hills. Mr. R. M. Laing, however, informs me that he' has collected plants of S. saxifragoides at various points on Banks Peninsula proper, in the neighbourhood of Akaroa, and it has been seen above that both Kirk and Cheeseman give Banks Peninsula as a locality for the species. It may be suggested that states of S. lagopus, “some of which,” as Cheeseman says, “approach it very closely,” have been mistaken for S. saxifragoides. In any case, I cannot say that I have found any examples of undoubted S. saxifragoides, having no bristles at all, on Banks Peninsula proper.

    On the other hand, no plants of typical S. lagopus were found by me anywhere along the Port Hills, though, as shown above, plants were frequently found in that locality which showed more of the special characters of S. lagopus than have hitherto, apparently, been observed or recorded.

    Except for a doubtful record in the Kaikoura neighbourhood, Seneciosaxifragoides seems to be confined to this locality. Forms observed by me in April, 1917, on Mount Fyffe and some other points on the Seaward Kaikouras were all typical S. lagopus.

    The specimens collected from Banks Peninsula and the Port Hills were preserved and fixed in such a manner as to make confusion impossible, and were then submitted while still fresh to Dr. Cockayne, together with certain inferences and conclusions to be drawn from them.

    While both plants show a preference for high rocky situations and dark, cold faces, neither is by any means restricted to such localities. Both are

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    found growing among tussock and occasionally on northerly faces, and both descend nearly to sea-level in situations backed by high hills, but apparently not otherwise. It may be conjectured that both were far more widely distributed (within the limits here described) before the advent of white men, for where the ground has been permanently fenced and protected from stock S. lagopus in particular, grows freely at a distance from rocks, especially on steep slopes and those facing south and south-west (as on the old Summit Track, where it rises to the ascent of Mount Sinclair on the south side, and where it runs along the southerly flank of Mount Herbert). Both also are found to grow among grass, & c., at the foot of cliffs and crags; but here, being accessible to stock, they live but precariously, and cannot form the large masses in which they cluster upon the rocks themselves. Thus both species, while now almost purely rupestral in their habit, were probably present in quantities over a very large area where they can now obtain no foothold.

    4. Conclusions.*

    1.

    Cockayne's surmise in regard to the restriction of the habitat of S. saxifragoides is proved to be absolutely correct, though it is possible that the plants of the Mount Herbert district are intermediate or even hybrid forms.

    2.

    The “bristles” of Hooker's, Raoul's, and subsequent descriptions are simply glandular hairs, and both species bear them, though in varying quantity and differently distributed upon the leaf in the two cases.

    3.

    Both species, in common with S. bellidioides and S. Haastii, have typical hydathodes at the ends of the veins, and both bear purple glandular hairs which are not mentioned in previous descriptions.

    4.

    Neither species has the glandular hair or “bristle” as a distinctive character. The two species differ from one another only in respect of the frequency and locality of occurrence of both glandular hairs (“bristles”) and silky hairs. Those differences in degree, being certainly hereditary, constitute true unit characters. The two kinds of hairs are thus unit characters common to the two species, but the abundance or sparseness of such hairs is a unit character peculiar to either species, as the case may be, and their sole distinction,

    5.

    As the two groups of individuals keep their individuality, each in its isolated, fairly wide area, they are almost certainly microspecies, and they should be grouped together as an aggregate, with saxifragoides as the name of one, group and some other name for the lagopus group. It would seem advisable that S. bellidioides, S. Haastii, and S. southandicus should also be brought into this aggregate, since they have in common with them the woolly rootstock, marginal hydathodes, and glandular hairs upon the surface and the margin of the leaf.

    6.

    Such varieties as the two under consideration, which have every distinguishing character in common, and which differ only in the hereditary degree of intensity, or the distribution of such characters, form a class of varieties (microspecies) different from those which are usually considered such through their possession of one or more quite distinct characters.

    7.

    The question whether the remarkable variation of S. saxifragoides can be explained at all is only approached here with extreme caution and

    [Footnote] * Regarding these conclusions I have consulted Dr. Cockayne, and they owe their present for to his suggestions.

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    • diffidence. As it is well established that the occurrence of silky hairs in great quantity is a xerophytic phenomenon,* it might be suggested that this character in S. saxifragoides is of climatic origin. The Port Hills, upon which S. saxifragoides flourishes, are nowhere higher than 1,800 ft., and most of the seven or eight high points upon them are between 1,500 ft. and 1,800 ft. in height; while the Akaroa peaks are on the average about 800 ft. higher than this, and Mount Herbert just exceeds 3,000 ft. As a consequence, the rainfall on Banks Peninsula proper is, and presumably has been for ages, considerably greater than on the Port Hills, the annual rainfall at the Convalescent Home station on the Port Hills being 25–52 in., while that of Akaroa is 44–72 in. There is no geological evidence to show that, since the formation of Lyttelton and Akaroa volcanic areas, Banks Peninsula proper and the Port Hills have not always stood in the same relation to one another as at present in respect of altitude, rainfall, and climate generally, though when the level of the whole was higher than at present, as it once undoubtedly was, the rainfall upon the Port Hills might have been more greatly reduced, relatively, than that upon Banks Peninsula proper. It might thus be argued that the drier climate of the Port Hills has directly determined the development of S. saxifragoides as above outlined. If this were the case we should expect to find similar forms developed in other dry localities, but it is doubtful whether any equally suitable situation exists within the limits of distribution of S. lagopus. If the Port Hills form a unique locality in this respect one could understand how S. saxifragoides has such a narrowly restricted range.

    Upon this theory S. saxifragoides and S. lagopus would be classed as two varieties of the same plant, differing only in the degree of efficiency reached, under stress, in the development of their xerophytic apparatus.

    Presumably, also, the other peculiarities of these two plants, such as the woolliness of the rootstock and petiole, might be assigned to the same general cause. Presumably all the six structures above described upon the leaf of S. lagopus, except, perhaps, the marginal glandular structures, would perform a similar function, though attention has here been confined to those two which characterize the upper surface of the blade of the leaf.

    I desire to express my acknowledgements, first, to Dr. L. Cockayne, F.R.S., to whom I owe the original suggestion of this paper, and without whose kindly encouragement and invaluable aid the work could not possibly have been carried out by me; also to Miss E. M. Herriott, M.A., assistant in the Biological Laboratory, Canterbury University College, who made the microscopical examinations of the various structures and described them (as above) in the most able manner; and, finally, to Mr. R. Speight, M.Sc., F.G.S., Curator of the Canterbury Museum and Lecturer in Geology at Canterbury University College, who supplied the geological history of Banks Peninsula here given, and also very kindly photographed for me the plants of Senecio lagopus on Mount Sinclair (Plate XIII).

    [Footnote] * E. Warming, Oecology of Plants, pp. 114, 193, 1909.

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    Art. XXII.—Descriptions of New Native Flowering-plants.

    [Read before the Auckland Institute, 11th December, 1917; received by Editors, 24th December, 1917; issued separately, 10th June, 1918.]

    1. Myosotis cinerascens sp. nov.

    M. perennis, follis culmisque pilis albis subrigidis appressis cinerascentibus. Culmi a radice complures graciles simplices vel parce divisi, 10–20 cm. alti, paene ad racemorum basim foliosi. Folia radicalia anguste obovato-spathulata ± 4 cm. longa circa 8 mm. lata obtusa, petiolis laminas aequantibus; caulina approximata consimilia ± 1.5 cm. longa lineari – obovata sessilia acuta. Racemi plenunque ± divisi breves subcapitati, raro simplices ac elongati. Flores albi breviter pedicellati; calyx ± 4.5 mm. longus, pilis rigidis patentibus subuncinatis dense hispidus, lobis brevibus acutis; corolla calyce subduplo longior anguste infundibuliformis, tubo lobis rotundatis brevibus ter quaterve longiore; stamina lineari-oblonga filamentis gracillimis duplo longiora, ad squamarum apices pertinentia; stylus maturus calycem ter quaterve superans. Nuculi oblongi, ter longiores quam lati, tenues brunnei.

    Perennial, ashy-grey in all its parts. Culms from the root few or several, erect or ascending at the base, simple or sparingly branched, 10–20 cm. (4–8 in.) high, slender, leafy to near the base of the inflorescence. Radical leaves narrow obovate-spathulate, ± 4 cm. (1 ⅔ in.) long, 8 mm. (⅓ in.) broad, gradually narrowed into petioles about as long as the blades, obtuse rather membranous, densely hispid on both surfaces with rather long stiff appressed whitish hairs; midrib little conspicuous; cauline all much alike, closely placed and usually overlapping, linear-obovate acute sessile, about 1.5 cm. (⅔ in.) long. Racemes usually closely branched, short subcapitate, more rarely simple and more or less elongated. Flowers white on strongly hispid pedicels; calyx ± 4.5 mm. (⅙ in.) long, equalling or exceeding the pedicels, densely hispid with stiff spreading more or less hooked hairs, cut for about one-third its length into narrow acute lobes; corolla narrow funnel-shaped, nearly twice as long as the calyx, cut into broadly rounded lobes one-fourth as long as the tube; stamens linear-oblong, twice as long as the very slender filaments, reaching quite to the top of the scales; style slender, longer than the corolla, and ultimately about thrice as long as the calyx. Nutlets oblong, thrice as long as broad, thin, dark brown, shining.

    Hab. — Limestone shingle-slip, Trelissick Basin, North Canterbury; 730 m. alt.: L. Cockayne! Broken River, on limestone debris, Canterbury Alps; 2,400 ft.: D. P.

    This species is allied to Myosotis Traversii Hook. f. as Cheeseman understands that species, but by no means closely. It was almost certainly included in M. Traversii by Hooker f., and is no doubt the plant from the “Waimakeriri Valley” mentioned on page 195 of the Handbook of the New Zealand Flora. The specimen examined do not show the radical leaves in good condition, while the corollas are more or less withered and shrivelled.

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    2. Myosotis saxatilis sp. nov.

    Perennis, pilis subtilibus brevibus albidis appressis viridi-incana. Caules pauci graciles, 8–12 cm. alti, supra pro parte tertia nudi. Folia radicalia obovato-lanceolata, 3 cm. longa 8 mm. lata, obtusa v. subacuta in petiolum sublatum angustata; caulina pauca subdistantia sessilia lineari-lanceolata acuta, radicalibus ½ breviora. Racemi conferte ramosi, ramia brevibus; flores 9 mm. longi, albi. Calyx alte 5-partitus, lobis linearibus; corolla infondibuliformis, tubo sublato calycem duplo superante; stamina corollae tubo vix breviora ad faucis squamas pertinentia; filamenta antheris breviora.

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    Perennial, greenish-grey, everywhere hoary with delicate short appressed whitish hairs. Stems few from the root, slender, more or less ascending at the base then erect, the upper third naked, 8–12 cm. (3 ½–5 in.) high. Radical leaves rather numerous forming a compact rosette, obovate-lanceolate, 3 cm. (1 1/5 in.) long, 8 mm. (5/16 in.) broad near the tips, rather membranous, obtuse or subacute slightly apiculate, gradually narrowed into rather broad petioles about as long as the blades; midrib evident, otherwise nerveless: cauline leaves few, rather distant, sessile or the lowermost shortly petiolate, linear-lanceolate, acute or subacute, about half as long as the radical. Racemes compactly branched, branches short; flowers crowded, fairly numerous, almost sessile, 9 mm. (⅜ in.) long, white. Calyx deeply 5-partite, lobes linear acute, sparsely clothed with more or less spreading hairs; corolla funnel-shaped, the tube rather wide and twice as long as the calyx, lobes spreading shortly oblong obtuse; stamens slightly shorter than the corolla-tube, reaching just to the level of the prominent throat-scales; anthers short, broadly linear, filaments about half as long as the anthers; style as long as the corolla and elongating after flowering. Mature nutlets not seen.

    On dry rocks, Shingly Range, Awatere Basin, Marlborough; about 4,000 ft.

    For the opportunity of examining this plant I am indebted to Dr. L. Cockayne, F.R.S., F.L.S., of Wellington. Perhaps its closest ally is my M. oreophila.

    3. Myosotis diversifolia sp. nov.

    Species M. petiolatae Hook. f. affinis; differt caulibus erectis, foliis valde membranaceis, caulinis acutis, pilis foliorum culmorumque longioribus tenuloribus vix rigidis minus arcte appressis, pedicellis brevioribus, corollae tubo duplo longiore, antheris angustioribus subapiculatis.

    Perennial; stems several (usually three or four) from the top of the moderately stout root, slender leafy to near the base of the racemes, simple or forked at the point of origin of the inflorescence, rather sparingly clothed with soft spreading white hairs, 8 in. (20 cm.) high or less. Leaves very membranous, sparsely clothed on both surfaces and along the edges with soft loosely appressed rather long delicate hairs, with a conspicuous rather fine submarginal nerve running all round; radical ± 2 ½ in. (6.3 cm.) long, blade elliptic 1 ⅛ in. (2.8 cm.) long, ¾ in. (2 cm.) broad, apiculate, sharply contracted into rather narrow softly pilose petioles somewhat longer than the blades; cauline progressively smaller and narrower, distant (internodes ½–¾ in. long), the lower shortly petiolate, the upper sessile by a broad base, all acute and apiculate. Racemes ± 3 in. (7.5 cm.) long, simple or forked many-flowered Flowers ¼ in. (6–7 mm.) long, white, shortly pedicelled

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    (pedicels shorter than the calyx), ebracteate, crowded in the earlier flowering stage; calyx ± ⅙ in. (4 mm.) long, cut half-way down into narrow ovate acute strongly ciliated lobes with short spreading hooked hairs at the basal part; corolla funnel-shaped, tube about twice as long as the calyx, narrow below, cut above into rather short rounded lobes; scales of the throat short and broad; stamens inserted a little below the scales, reaching as high as the clefts of the corolla-lobes; anthers narrow, scarcely elongated, almost apiculate, about three times as long as the very slender filaments to which they are attached a little below the middle; style short, scarcely exceeding the calyx even in fruit; nutlets (scarcely mature) pale brown, suborbicular.

    Hob.—Ruahine Mountain-range, above the forest-belt.

    Collected by Mr. H. Hill, B.A., of Napier, to whom I am indebted for specimens.

    Mr. Cheeseman (Manual, p. 468) referred this plant to M. petiolata Hook. f. The latter is a coastal form, and it is doubtful if it ever grows inland or at considerable elevations. In my view M. petiolata is a purely coastal form, the montane plants referred to it probably belonging elsewhere. I am not certain of the colour of the corolla when fresh.

    4. Myosotis tenericaulis sp. nov.

    M. annua(?) M. spathulatae Forst. f. affinis; differt caulibus primo suberectis demum ± late diffusis, 20–30 cm. longis, valde tenuibus flaccidisque; caulibus foliisque cineraceis; floribus minoribus; corollae tubo limbi divisuras bis terve superante; antheris anguste oblongis subapiculatis filamenta excedentibus, vix ad faucis squamas breves latas manifestas pertinentibus; nuculorum integumentis pallide flavidis, nucleo atriore per integumenta ± pellucida manifesto.

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    Annual (?); stems numerous from the root, 20–30 cm. (1 ft. or less) long, suberect below, spreading and diffuse above, sparingly and distantly branched, branches elongated (internodes long), very thin and flaccid, like the leaves ashy-grey, slightly hispidulous with short appressed whitish hairs, rarely nearly glabrous. Leaves very thin, often subapiculate, with evident midrib, sparsely sprinkled with short appressed whitish hairs, the lower surface sometimes nearly glabrous; radical 3.5 cm. (± 1 ¼ in.) long, the blades elliptic-obovate contracted into slender petioles nearly twice as long as the blades; cauline distant, smaller, narrow-obovate, sessile by a broad base, obtuse or the uppermost subacute. Flowers solitary distant, usually opposite the axils of the upper cauline leaves, on very slender pedicels about as long as the calyx; calyx narrow ± 2 mm. (about 1/14 in.) long, cut nearly to the base into linear subulate segments, sparingly hispidulous with the usual appressed hairs; corolla narrow funnel-shaped, the tube about one-half longer than the calyx, lobes broadly rounded about one-third as long as the tube; throat-scales short and broad; stamens narrow-oblong subapiculate, scarcely reaching to the level of the scales; filaments very short, affixed to the anthers near the base; style slender, equalling the corolla, and scarcely elongating in fruit. Nutlets shining, pale yellow especially at the thin margins, elsewhere brownish owing to the deeper colour of the nucleus of the seed showing through the rather pellucid integuments.

    Hab.—Inch-Clutha, Clutha County. The exact locality where this plant was collected can be easily found. It is about a mile from the Romahapa

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    station on the Catlins River railway line, where the line crosses the Puerua Stream and enters the alluvial plain of Inch-Clutha. It grew in moist spots alongside the creek.

    Mr. Cheeseman (Manual, p. 467) doubtfully referred this plant to M. spathulata Forst. f., which is its nearest ally, though not a very close one. He further mentions that it has been collected by the late Mr. T. Kirk near Winton, Southland County. It appears to be confined to the southern lowlands of Otago.

    5. Myosotis macrantha Hook. f. var. westlandica var. nov.

    A forma typica differt foliis radicalibus longioribus multo tenuioribus anguste obovatis molliter pilosis, venis a costa ad venam submarginalem conspicuam oblique progredientibus, culmis longioribus gracilioribusque, floribus flavis.

    In a moist shady ravine on Rangi Taipo, Jackson's, Taramakau River; about 4,000 ft.: L. Cockayne, D. P.

    When better known this form may prove to be a distinct species; for the present it seems better to rank it as a variety.

    6. Pterostylis areolata sp. nov.

    Gracilis glabra ± 15 cm. alta. Folia pauca, caulina, sessilia, culmum amplectentia; inferiora scariosa squamiformia; superiora (plerumque 3) valde tenuia, in siccitate pellucida, lanceolata v. oblongo-lanceolata, acuta v. subacuta, plurinervia manifeste areolata, 3.5–4 cm. longa 1 cm. lata; culmo folium summum longe excedente. Flores solitarii 3.5 cm. longi ± 1.5 cm. lati. Galea pro parte majore erecta, pro parte tertia recurva; sepalum superius in apicem brevem acutum haud filiformem desinens, petalis acutis paulo longius; labii inferioris divisurae anguste obcuneatae, in apices subulato-filiformes summam galeam haud excedentes desinentes; labium subcrassum lanceolato – oblongum subacutum; columna gracilis elongata galeae partem erectam aequans.

    Slender, glabrous, ± 15 cm. (6 in.) high. Leaves 4 or 5 (in the specimens seen), rather distant, sessile and sheathing the stem; the lower reduced to scarious sheathing scales; the upper very thin, pellucid when dried, 3.5–4 cm. (± in.) long, 1 cm. (± ⅜ in.) broad, lanceolate or oblong-lanceolate, acute or subacute, entire, narrowed towards the base, with conspicuous veins running nearly straight along their whole length and connected by delicate more or less oblique veinlets into an open network; the uppermost leaf placed about half-way up the stem and reaching about half-way up to the flower. Flowers solitary, 3.5 cm. (± 1 ½ in.) long, ± 1–5 cm. (⅝ in.) broad, green more or less streaked with reddish-brown; galea erect for two-thirds its length, then sharply bent forwards; upper sepal ending in a short more or less acute non-filiform tip, a little longer than the acute petals; lower lip narrow-cuneate for nearly half its length, forking widely into narrow obcuneate subulate-filiform-tipped lobes that do not exceed the top of the galea; lip brownish when dried, rather thick and firm, lanceolate-oblong, subacute with exserted tip; column slender, as long as the erect part of the galea, the lower lobe of its wings large long obtuse.

    Hob.—Base of Shingle Peak, Awatere Valley, Marlborough; 3,000 ft.; in shade: L. Cockayne! Bealey, Waimakariri Valley, Canterbury: T. Kirk!

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    This appears to be a well-marked species. The late Mr. Kirk referred his specimens, which are in fruit and are rather stouter than Dr. Cockayne's, to P. micromega Hook, f., but they are destitute of radical leaves, while the cauline leaves are much larger and broader than those of P. micromega, and do not extend above the middle of the stem. As I have seen, only dried specimens, the details of the structure of the column may be imperfectly sketched here.

    7. Poa campbellensis sp. nov.

    Species P. pusillae Berggren affinis: differt foliis numerosis erectis v. suberectis conduplicatis apice obtusis; ligulis longioribus ± oblongis laceris v. erosis; spiculis paulo majoribus viridibus colore purpureo-spadiceo ± tinctis; glumis florigeris subacutis basi pilis crispulis brevibus exigue instructis; paleis apice subalte bifidis ac a carinis delicate ciliatis.

    Culms very slender densely tufted, leafy below and usually clothed by the sheaths of the cauline leaves to above the base of the panicle, 5–10 cm. (2–4 in.) rarely 15 cm. (6 in.) high. Basal leaves much shorter than the culms, erect or slightly spreading, narrow blunt-pointed, smooth, folded, rather stiff; sheaths about as long as the blades, broad, thin, loose, membranous, striate; ligules variable in length, shortly oblong (rarely longer and narrowed upwards), thin and scarious, erose or lacerate at the tops.' Panicle small, 2.5–4 cm. (1–1 ½ in.) long, narrow-ovate, of 6–9 spikelets placed on rather long glabrous or slightly scabrid pedicels; branches capillary, the lower much longer. Spikelets ± 7 mm. (¼ in.) long, ovatelanceolate, greenish, faintly stained with purplish-brown, 2–3-flowered; outer glumes slightly unequal, about two-thirds as long as the flowering-glume immediately above, smooth or slightly scabrid along the keel; the lower narrow-ovate acute faintly 3-nerved, the upper broader subacute strongly 3-nerved; flowering-glumes ovate-oblong, subacute, thin, more or less scarious around the tops, smooth except on the finely scabrid keel, with a scanty tuft of delicate crisped hairs at the callus, 5-nerved; the two lateral nerves faint, the median nerve alone reaching the top; palea a little shorter than the flowering-glume, rather deeply bifid at the top, finely ciliate along the nerves.

    Hob.—Campbell Island, and Port Ross in the Auckland Islands: B. C. Aston! (January, 1909).

    The Port Ross specimens are considerably taller than those from Campbell Island. In my report on the Gramina in vol. ii of The Subantarclic Islands of New Zealand this grass was united with my Poa incrassata. I am now satisfied that this treatment of the plant is incorrect. The original description (Trans. N.Z. Inst., vol. 34, p. 394, 1902) and that given in Mr. Cheeseman's Manual (p. 911) are therefore the correct ones. Mr. Cheeseman has noted that Poa incrassata is most nearly allied to Poa exigua Hook. f. The present species has its nearest ally in Poa pusilla Berggren.

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    Art. XXIII.—The Geomorphology of the Coastal District of Southwestern Wellington.

    [Read before the Wellington Philosophical Society, 12th December, 1917; received by Editors, 31st December, 1917; issued separately, 10th June, 1918.]

    Plates XIV, XV.

    Contents.
    • Introduction.

    • The Foundation or Old Land.

    • The Coastal Lowland.

    •    Theoretical Discussion of the Growth of a Coastal Lowland under Conditions of Fluctuating Waste-supply.

    •    An Alternative Explanation.

    •    The Paekakariki Coast.

    •    Another Alternative Explanation.

    • Subdivisions of the Lowland.

    •    The Otaki Series.

    •       Topography of the Otaki Series.

    •       Distribution of the Otaki Series.

    •       Lithology and Structure of the Otaki Series.

    •    The Fans or Gravel Plains.

    •    The Delta of the Manawatu.

    •    The Modern Dunes.

    •    Lakes and Swamps.

    Introduction.

    The coastal district of south-western Wellington (fig. 1), forming part of the fertile “Manawatu” and largely comprised within the limits of Horowhenua County, presents a considerable variety of physiographic features all of comparatively modern growth* and explicable on an assumption of a geological history of a somewhat unusual kind.

    I have been informed by Dr. L. Cockayne and Mr. A. H. Cockayne that the ecology and agriculture of the district are closely related to the physiography, and I am tempted to present this somewhat sketchy description and attempted explanation of the forms in the hope that it may be of use as a basis for further studies.

    The Foundation or Old Land.

    The skeleton or foundation of the coastal district of south-western Wellington is the upland block of somewhat old rocks sculptured into strong relief that forms the Tararua Mountains and the lower ridges farther south. Lithologically these rocks are greywacke-sandstones with occasional bands of argillite, the latter much sheared by earth-movements. All are closely

    [Footnote] * Geologically the whole history of the lowland is comprised within a portion of the Notopleistocene period.

    [Footnote] † The early geologists termed these rocks the “Rimutaka series,” a local name that might be now appropriately used for them. Subsequently to the issue of the geological map of 1873 the name “Rimutaka” gave place to “Maitai,” as it was believed that the two formations were identical; but it was used occasionally by McKay in the “seventies” for the whole or part of the rocks of the Rimutaka and neighbouring ranges.

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    folded, so that the strata are now everywhere nearly vertical, and the strike, though variable from point to point, averages a little to the east of north. Some bands of the rock are thoroughly shattered and allow of the percolation of water along closely spaced joints, so that they yield rather readily to deep weathering and erosion. Other hands have escaped shattering or have had the network of crevices re-sealed by a deposit of secondary mineral matter, so that there are now few joints, and weathering and erosion, go on relatively slowly. These latter relatively resistant bands of rock stand out boldly as ridges, while the bands of shattered rock are now followed by streams, and, where of considerable breadth, are reduced to somewhat subdued forms with moderate relief.

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    Fig. 1.—Map of the coastal district of south-western Wellington, including the upland ranges eastward to the main divide. Scale, 10 miles to 1 in. The inset map shows the locality.

    It is not known with certainty that the alternating bands of resistant and weak rocks, which owe their varying strength, as just noted, to the extent to which they are fissured, correspond exactly to the bedding; but they are at least elongated in the same general north-north-easterly direction, and the shattering in the weakened bands was probably caused by

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    the ancient folding. (An exceptional belt of shattering close to the city of Wellington, which crosses the strike diagonally, is not here referred to. It appears to be connected with fault movements of a much later date than the folding of the rocks.*)

    The texture of the dissection on both the higher ridges of resistant rock and the lower belts of subdued topography is somewhat fine, owing, no doubt, to the low permeability of the mantle of residual clay that results from the weathering of the greywacke.

    The development of the present mature topography seems to have been interrupted from time to time by renewed uplift, as in the Wellington peninsula farther to the south-west, but the high valley-floors of the earlier cycles are here maturely dissected, and the land-forms of the various cycles merge almost or quite completely into one another. Some of the later pauses in the uplift are probably recorded by the fragmentary terraces in some of the valleys. These are generally rock terraces, but some are formed of alluvium—e.g., in the Otaki valley a thick mass of fluviatile gravel underlying a portion of a terrace and extending below the present level of the river suggests trenching, due to uplift, and later refilling of the trench, perhaps during a temporary submergence preceding an uplift to which the cutting of the present narrow inner valley of the river is due. The terrace features cannot be ascribed wholly to vertical movements of the land, however, for they must be closely connected with certain to-and-fro movements of the shore-line which will be described below.

    The margin of the upland block is a mature coast-line rising in places as high cliffs, but fronting the sea now only at the south-western end, beyond the limits of the district here dealt with, and bordered elsewhere by a coastal lowland the width of which increases north-eastward. With respect to this lowland of later growth the upland block may be spoken of as the “old land.” The ancient coast-line of the old land appears to have originated as a fault coast, for its almost straight north-east and south-west trend crosses the grain of the country obliquely. Whatever the initial form may have been, however, a mature coast of simple outline developed by marine erosion now forms a nearly straight boundary-line between the upland block or old land and the strongly contrasted coastal lowland.

    The Coastal Lowland.

    Different parts of the coastal lowland are of different ages, and their present topographic forms have been developed in different ways, and the materials of which they are composed, though in some cases originally identical, are in different stages of consolidation and decay, so that they yield very different soils. The materials also came originally from two distinct sources.

    The divisions of the lowland are best introduced by a discussion of the conditions under which it seems to have come into existence. All the features of the lowland may have been produced by an alternation of retrogradation (or retreat of the shore-line under wave-attack) with progradation (or advance of the shore-line due to accumulation of the waste of the land). Such an alternation is necessarily connected with a fluctuation in the supply

    [Footnote] * G. A. Cotton, Supplementary Notes on Wellington Physiography, Trans. N.Z Inst., vol. 46, pp. 294–98, 1914.

    [Footnote] † C. A. Cotton, Notes on Wellington Physiography, Trans. N.Z. Inst., vol. 44, pp. 245–65, 1912.

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    of waste, leading to a fluctuation in the ratio of wave-energy to load, for, when the supply of waste is small, waves attack a coast vigorously, cut it back, and draw much of the waste produced in this process back into the deeper water off shore, where it comes to rest; whereas when there is a large supply of gravel or sand, either brought in by local rivers or transported along-shore by the activity of waves and currents from a more distant source, the energy of the waves is used up in maintaining a graded off-shore profile of the bottom as the abundant waste accumulates at all depths, and some of the material is thrown up on the beach, so that the shore-line advances seawards, leaving a prograded strip of new land.

    In the case in question it is probably the supply of sand, which comes from rivers farther to the north-east, that has fluctuated, rather than that of gravel brought down by local streams. The cause of the fluctuation is not apparent. Changes of level of small amount would have an effect, no doubt, by disturbing the graded profile of the neighbouring sand-covered sea-bottom, and would perhaps produce alternate overloading and underloading of the waves at the shore-line. The fluctuation in the supply of sand is too great, however, to be attributed to that cause alone. I have not recognized the concomitant effects of such small movements on the coastal topography, nor succeeded in distinguishing them from the effects of advance and retreat of the shore-line, and so they are necessarily ignored in this account.*

    Theoretical Discussion of the Growth of a Coastal Lowland under Conditions of Fluctuating Waste-supply.

    Where a coast, perhaps originally a fault coast—though this is not essential—has been cut back to the mature stage, like the ancient coast of the old land of south-western Wellington (fig. 2, A), and a change to progradation takes place, a strand-plain, generally dune-covered, is developed (fig. 2, B). The material is mainly “imported” sand, if it is assumed that the excess of material has been brought from another section of the coast, but there will be mixed with it some gravel of local origin near the mouths of streams. As the streams grow in length seaward, however, with the growth of the prograded strip, they are constrained to aggrade so as to build up channels with sufficient slope to maintain their flow, and a proportion, perhaps the whole, of their gravel is thus used up, and accumulates as fans along the base of the cliffs of the old land (fig. 2, B), Clearly, if these streams are somewhat closely spaced and bring down much gravel their fans will become confluent, forming a piedmont alluvial plain; but, on the other hand, if their supply of gravel is smaller in proportion to the amount of sand being thrown up along the shore-line they will remain separate, and on the spaces between them dune sand may accumulate to a considerable thickness.

    There is thus developed a coastal lowland of general seaward slope, with a somewhat irregular surface, and possibly with a width of many miles.

    [Footnote] * Adkin reports that a trial well-boring on the lowland passed through a swampy layer (i.e., a land surface) far below present sea-level (Trans. N.Z. Inst., vol. 43, p. 498, 1911). I have not been able to obtain official records of any of the bores that have been put down; but if this interpretation is correct it indicates that the lowland, during an early period of outward growth, advanced, or was at least maintained, in spite of considerable subsidence (as in the case of the Canterbury Plain). To make this possible the supply of waste at that stage must have been very abundant.

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    If now the landward dunes have become fixed by vegetation and somewhat consolidated, they will in time have a normal drainage system developed on them, and their irregularity of surface will be reduced by the filling of the hollows and the wearing-down of the initial hills, so that their surface will become a peneplain (fig. 2, C).

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    Fig. 2.—Diagram of successive stages in the growth of a composite coastal lowland during two periods of progradation separated by one of retrogradation.

    If now after a period of slow progradation, perhaps followed by a period of stationary shore-line, retrogradation begins again, the seaward-sloping coastal lowland, as its toe is cut back to a line of cliffs of growing height, will be dissected owing to the shortening of its streams. Since the dunesand areas lie between the larger streams from the old land, they will be traversed only by systems of small streams arising on them or heading on the cliffs behind. The energy of such streams is slight, but they work on very weak material and so erode quite rapidly (fig. 2, D). The larger streams from the old land will now trench the fans they formerly built, and they may destroy the fansurface altogether or reduce it to fragmentary terraces, developing streameroded plains at lower levels, which may in places be widened so as to plane down parts of the dune-sand areas.

    The lowland will now resemble in a general way a dissected coastal plain of subaqueous origin, but there will be differences in detail, for the initial form in this case is a subaerially graded surface, and when the streams entrenched below it have again become mature the slopes of their valley-plains will approximate to that of the interfluves, and also such of the interfluvial areas as are underlain by dune sandstone will not be quite flat, but will retain the small relief of a peneplain.

    There may be pauses in the retrogradation of the coast, and even reversals from time to time, and thus several series of terraces or valley-in-valley forms may be developed (fig. 2, E).

    It may be postulated that after the coastal lowland has been cut back by

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    the sea to perhaps half, or less than half, its former width progradation again sets in, and a new strand-plain, dune-covered like its predecessor, grows seaward from the recently cut cliffs. This will give rise to various modifications in the form of the dissected lowland. It will cause vigorous aggradation in all the gravel-bearing streams from the old land, and some of these may completely fill the valleys they have previously excavated in the lowland. Thus the fans are reconstructed (fig. 2, F). Intercalated short periods of retrogradation or other causes may lead to channelling of the fans from time to time, followed by renewed aggradation, and similar results may be produced by fluctuation of level. Thus there may be a considerable amount of complexity in the structure of fans.

    Along the border of the inter-fan areas the even seaward slope of the lowland is not so readily restored. Some aggradation will take place, however, along the lines of the small dissecting streams, but irregularly, the greatest effects being seen where the channels, perhaps kept open for a time across the newer strand-plain, becomes blocked by sand-dunes, forming lakes partly within and partly beyond the border of the older dissected lowland (fig. 2, F). These, when filled, become swamps with arms extending up the floors of the tributary valleys, which are in process of aggradation with fine silt. Similar swampy flats will occur as normal features also among the dunes on the newer strand-plain.

    Meanwhile the cliffs along the toe of the older lowland will be reduced to gentler slopes by subaerial erosion, which goes on quickly in this soft material, and reduction of the surface will still continue. Parts of it are by now maturely dissected, and there may be close interfingering between the spurs of the older and the dunes of the newer lowland.

    In a coastal lowland developed as outlined above four quite distinct physiographic types of surface can be recognized: (1) The older dunesandstone areas of the dissected older lowland, with peneplained tops, mature topography towards the margins, and more or less dissected terraces in the valleys; (2) the gravel fans, which may still be confined between low banks of the dune sandstone or may overlap its peneplained surface; (3) the newer sand-dunes, which still exhibit the forms due to accumulation; and (4) swampy flats, which have accumulated in lakes due to ponding among the newer dunes or between these and the toe of the older lowland, or are the result of aggradation in the silt-bearing small streams trenching the older lowland. In the coastal lowland of south-western Wellington all four of these physiographic elements are important.

    An Alternative Explanation.

    An alternative explanation which would account for the existing forms in the broader part of the lowland fairly well would make the “older lowland” of the foregoing a coastal plain of subaqueous sands, which was subjected to subaerial erosion with the shore-line stationary for a period long enough to allow of peneplanation, and afterwards cliffed at the margin and dissected. The remaining events would be the same as those outlined in the previous explanation. An objection to this explanation is found in the nature of the material of the older dissected lowland, which will be referred to on a later page; and an argument in favour of the explanation previously given is found in the clearly decipherable history of the lowland at its extreme south-western end (at Paekakariki), where there is evidence of alternating progradation and retrogradation on a scale sufficiently large to warrant the assumptions made.

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    The Paekakariki Coast.

    South-westward from the tapering end of the lowland at Paekakariki the cliffed margin of the old land is now being cut back, and there is no evidence to show whether this part of the coast has ever been prograded. The dune-covered strand-plain is now extending in that direction along the base of a line of high, fresh cliffs cut diagonally across one of the resistant ridges of the old rocks (Plate XIV).

    A mile or two north-eastward, however, there is evidence of the former presence of a strand-plain and of its removal prior to the growth of the present lowland. This evidence is found in the presence of cliffed remnants of fans of locally-derived gravel, one of which is of such dimensions that the fan when complete must have extended seaward about a mule beyond the margin of the old land.

    These fans were built forward in what may be termed the first (strictly the nth) progradational phase (fig. 3, B), following the first (strictly nth) retrogradational phase, in which the cliffs of the ancient coast-line of the old land were cut (fig. 3, A). These cliffs are now subdued and rounded, and pass by smooth concave curves at the base into the fans and talus slopes.

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    Fig. 3.—Diagram of successive stages of a coast alternately retrograded and prograded.

    The fans are irregularly truncated by a younger line of cliffs developed in a second [(n+1)th] retrogradational phase, and these are cut back far enough in places to intersect the line of older cliffs (fig. 3, C). The cliffs previously referred to as lying behind the extreme end of the lowland are continuous with these of the second [(n+1)th] retrogradational phase.

    In front of this newer line of cliffs lies the modern lowland or dune-covered strand-plain, a belt of dunes enclosing between themselves and the cliffs a narrow strip of marshy plain (fig. 3, D). Fig. 4 is a panoramic sketch of this portion of the coast, illustrating the features described. Plate XV, fig. 1, is a photographic view showing the truncated fans.

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    Plate XIV.
    General view of the narrow southern end of the coastal lowland, looking northward from the cliffs south of Paekakariki.

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    Fig. 1 —Fan with cliffed seaward margin, north of Paekakariki
    Fig. 2.—Dissected bench of Otaki sandstone near Shannon

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    Fig. 4.—The Paekakariki coast, viewed from the modern fixed dunes. Angle of view, south-east to south-west.

    Another Alternative Explanation.

    An account of the geological history of the coastal lowland which diverges considerably from that assumed in the explanation of the physiography here adopted was given by Adkin,* whose account deals in particular with that part of the lowland adjoining the Ohau River.

    Adkin's classification of various stages in his concept of the history of the lowland as Early Pleistocene, Middle Pleistocene, Later Pleistocene (First, Second, and Third stages), and Recent must be discarded, as he had no means of correlation with deposits of Pleistocene age elsewhere; and for the present purpose the stages “Early Pleistocene” to “Recent” may be renamed stages 1 to 6.

    According to his interpretation, at stage 1 the Ohau River built a great fan over hypothetical undissected uplifted Pliocene formations with a plane surface, the latter being vaguely “inferred from the configuration and character of the superimposed fluviatile deposit.” Large parts of the surface of the fan formed at this time are regarded as surviving to the present day, though buried by a marine deposit and re-exposed by erosion in the intermediate historical stages.

    Stage 2 was a period of complete submergence of the lowland beneath the sea. This was followed by a period of still-stand, succeeded by uplift continuing to the present day. During the submergence at stage 2 a “raised-beach formation” was deposited, consisting of beach sands spread over the whole area of the lowland partly during the advance of the sea and partly during its retreat. This “raised-beach formation” comprises the partially consolidated sands of the older lowland. Adkin states that its present level surface is not the original one, as it has been lowered by erosion. It is not clear, however, to what base-level he ascribes the planation, or at what stage of the history it occurred. Dissection of the surface by small streams is mentioned in the description of an illustration.

    [Footnote] * G. L. Adkin, The Post-tertiary Geological History of the Ohau River and of the Adjacent Coastal Plain, Horowhenua County, North-Island, Trans. N.Z. Inst., vol. 43, pp. 496–520, 1911.

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    The remaining stages are marked by changes in the courses of the Ohau and other streams over the Ohau fan, for the explanation of which Ferrel's law is invoked, though it is much more probable that such changes as have taken place in stream-courses have resulted from spilling over as a normal accompaniment of aggradation. At the same time the shore-line advanced steadily seaward. It is not clear whether this is regarded as entirely the result of an inferred movement of uplift, but this is probably what the author had in mind, as he speaks of the whole lowland as a coastal plain. The new land formed thus was progressively covered with sand-dunes, which impounded lakes.

    The account is somewhat difficult to follow, but the foregoing is a fair summary. Adkin regards the gravel plains, such as the Ohau fan, as the oldest, instead of placing them among the youngest elements of the lowland physiography, as is done in the explanation now offered; and his conclusion that any portions of the existing fan-surfaces or gravel plains were in existence prior to the deposition of the sands of the older lowland is an extremely doubtful one, whatever the correct explanation of the mode of accumulation of those sands may be.

    It must be added that Adkin's work is obviously based on a large amount of careful field-work; and his mapping in the Ohau River district (Horowhenua) is extremely useful.

    Subdivisions of the Lowland.

    The Otaki Series.

    The oldest physiographic element in the lowland is, then, the dissected peneplain of soft sandstone corresponding to the “older dune-sand areas” of the theoretical discussion previously given, and comprising the “raised-beach formation” of Adkin. To the lithological formation of sandstone thus indicated the name Otaki series may be applied as a local formation name, as it is well developed just north of the Otaki River and town.

    Topography on the Otaki Series.—The topography is that described in the theoretical section as developed on the “older dune-sand areas,” and shown diagrammatically in fig. 2, F (see also Plate XV, fig. 2). I agree with Adkin* that the gently undulating tops of the broad benches of this formation are parts of a surface of erosion and not of deposition. In some parts of the district a considerable area of the surface of the Otaki series consists of broad terrace-remnants of valley-floors at intermediate levels developed generally by very small streams which now make their way along the flat, swampy floors of inner valleys. A striking characteristic of the small dissecting streams arising within this formation is the steepness of their valley-sides, which remains practically constant as the width of the floor increases, and the same slope continues around the valley-heads. To their very heads the valleys are box-shaped rather than V-shaped. The slopes separating the broad terraces at intermediate levels were evidently once exactly similar to those of the inner trenches, though they have become somewhat dissected and broken down since the streams were revived and undercutting of these slopes ceased. Where the terraces have been developed by gravel-bearing streams heading in the old land they are gravel-covered.

    Distribution of the Otaki Series.—Between the southern end of the coastal lowland and the Manawatu River the Otaki series, with its characteristic

    [Footnote] * Loc. cit., p. 509.

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    topography, covers an area of perhaps sixty square miles, of which about half consists of nearly flat summits. One considerable area occurs between the Otaki and Ohau Rivers; an “island” of it, surrounded by gravel plains evidently parts of the Ohau fan spread by distributaries of that river, occurs at Weraroa, where the Central Development Farm of the Department of Agriculture is situated partly on this formation and partly on the fan; and there is then a nearly continuous bench, broken only by some gravel-covered valley-floors, extending north-eastward for twenty miles.

    Lithology and Structure of the Otaki Series.—The prevailing material in the Otaki series is grey sand similar in mineral composition to that of the present beach and the associated dunes. In addition to quartz, the sand contains a considerable proportion of feldspathic, ferromagnesian, and iron-oxide grains. The mineral grains, including those of quartz, though not completely rounded, have their angles smoothed off, and they thus contrast very strongly with the sharp, angular grains of the present beach. This suggests aeolian accumulation. All the samples examined are somewhat weathered, however, and the rounding of grains may be ascribed in part to weathering.

    The more or less coherent sandstone formed of this material weathers at the surface to a residual sandy clay, usually containing scattered spheroidal masses of the sandstone. The permeability seems not to be great, for the water-table is generally close to the surface. Much water seeps out along the bases of even low scarps, and necessitates draining.

    In the few sections where bedding has been noted the beds are inclined at about 35°. It is quite clearly cross-bedding on a large scale, and again suggests subaerial accumulation. Cross-bedding and also ripple-mark are noted by Adkin.* A horizontal pseudo-stratification, due, apparently, to deposition of iron, is also generally present. Though less prominent, it seems to resemble that noted by Berkey in the aeolian San Juan formation of Porto Rico.

    The non-discovery of fossils, though a negative character, points also to the possibility of subaerial accumulation of the sand of the Otaki series.

    Clay lenses and bleached soil-beds, which are interbedded with the sandstone, accumulated, no doubt, in lakes and swampy areas impounded among dunes. The clay-bed between upper and lower sands noted by Adkin,§ which he ascribes to marine deposition at a period of maximum depression, is perhaps one of these.

    In one section near Shannon layers of small pebbles occur interbedded with the sand. Here is probably the course of one of the smaller streams from the old land, or perhaps the margin of one of the larger fans. If gravel fans and dune sands accumulated side by side, as is assumed in the theoretical section, there must be a considerable amount of intermixture of material along the transition lines where gravel passes laterally into sand. Along these lines, indeed, a complex interfingering of gravel and sand beds may be expected.

    The Fans or Gravel Plains.

    Throughout the length of the lowland there are numerous gravel fans, both great and small. The largest are those of the Otaki and Ohau Rivers,

    [Footnote] * Loc. cit., p. 507.

    [Footnote] † C. P. Berkey, Geological Reconnoissance of Porto Rico, Ann. N.Y. Acad. Sci., vol. 26, pp. 1–70 (see p. 50), 1915.

    [Footnote] ‡ G. L. Adkin, loc. cit., pp. 497, 507.

    [Footnote] § Loc. cit., p. 507.

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    which have a combined area of about forty square miles. Some parts of their surfaces are thickly covered with small boulders or coarse gravel; others have a gravelly soil; while others, again, have a superficial layer of silt overlying gravel. Most of the fans are trenched and terraced to a small extent. The surfaces of the fans and of terraces cut in them are very similar to one another, as are also gravel-covered terraces within the border of the old land. All these may be classed as gravel plains. The gravel-bearing streams are at present aggrading as though to refill the trenches in the fans. The actual stream-beds are, therefore, areas of bare gravel over which the streams flow in changing, braided channels. As previously mentioned, the upper surface of the Otaki formation passes in some places into that of a fan without any abrupt break of slope.

    The Delta of the Manawatu.

    More or less analogous with the fans of the southern part of the lowland is the delta of the Manawatu River; but this is one, perhaps the chief, of the sand-supplying rivers. Its delta is composed mainly of fine material, and its gradient is very gentle as compared with that of the gravel fans. The Manawatu delta forms a plain of wide extent lying at present almost entirely on the north side of the river, and continued up-stream by a wide flood-plain, below which the river is now slightly entrenched, and above which there are broad terraces on the northern side. The seaward margin of the delta is covered with dunes, some belts of which extend inland many miles. The Manawatu River at present bends to the south-west after emerging from its gorge across the old land, and at a not very distant date it swung still farther to the south. The toe of the bench formed by the Otaki series is here cut back to a line of cliffs by the action of the river, and at the base of these a considerable area of ill-drained flood-plain, now abandoned by the river owing to its slight entrenchment, forms the great Makurerua Swamp (see fig. 1). The whole of the delta plain was formerly swampy, but a great part has been artificially drained.

    The Modern Dunes.

    The modern dunes are built of grey sand similar to that forming the sandstone of the Otaki series. All except a narrow belt close to the sea are fixed by vegetation, but beneath the superficial layer of humus the sand is still quite loose. The belt of dunes has a width of from three to six miles, and their average height is 170 ft. Adkin notes that their general arrangement is in ridges at right angles to the coast-line.* The shore-line of the dune-covered foreland advances as a broad cusp towards Kapiti Island (a high island of old rocks some four miles from the mainland). This is evidently an early stage of island-tying.

    Lakes and Swamps.

    Several lakes and many small ponds and swamps formed by the silting-up of ponds lie between the modern dunes and the margin of the other physiographic elements of the lowland, and there are many swampy areas among the modern dunes. The valley-floors in the Otaki formation are practically all swampy, as a result either of normal aggradation with fine silt or of ponding by sand-dunes followed by accumulation of silt. The largest swamp in the district—the Makurerua Swamp—has been referred to above

    [Footnote] * G. L. Adkin, loc. cit., pp. 514–15.

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    Art. XXIV.—New Zealand Ironsands: an Historical Account of an Attempt to Smelt Ironsands at Onehunga in 1883.

    [Read before the Technological Section of the Wellington Philosophical Society, 13th June, 1917; received by Editors, 31st December, 1917; issued separately, 17th June, 1918.]

    It is extremely difficult after a lapse of nearly thirty-five years to obtain a complete history of this undertaking, as the directors of the New Zealand Iron and Steel Company (Limited) are all dead—in fact, almost everybody who had any connection with it. Its records have been lost or destroyed, and the only data I have have been obtained from a private letter-book and a few odd documents which I found amongst my father's papers.

    In 1866 Mr. John Chambers arrived in New Zealand, and soon afterwards saw the ironsand on the beaches of Taranaki. He was much impressed with it as a valuable asset, if the material could be converted into marketable iron. From some early settlers he learnt that 100 tons of sand had been sent to Staffordshire, where it was manufactured into iron by David Hipkins, who wrote that he smelted and puddled the sand into bars, sheets, hoops, boiler-plates, and fencing-rods, afterwards making it into horse-shoes, chain, &c. All were tested and pronounced equal to any of the Staffordshire irons; but owing to cost of manipulation he would not recommend his principals to obtain further supplies or establish a works in New Zealand.

    Later, in 1876, Mr. Chambers took a parcel of ironsand to England and the United States. He interviewed many ironmasters, but could get none sufficiently interested to experiment seriously with the samples, excepting in laboratories, where a few pounds of iron and steel were produced in crucibles.

    In 1886 I attended the Indian and Colonial Exhibition, where there were exhibited a parcel of sand and some iron manufactured by the above company. While in London I was introduced to W. T. Jeans, Price Williams, and Sir Henry Bessemer, all of whom were interested in the sands of New Zealand and Canada. Arrangements were made with Sir Henry Bessemer to carry out a series of experiments. His report was unsatisfactory, for, although he claimed that the best-quality iron and steel could be produced, it would require a great deal of research work, and he was too old to go on with it.

    Just before Sir William Siemens died, in 1883, he stated that his attention had been called to the ironsand in New Zealand and Canada, containing about 50 per cent. of metallic iron, and he demonstrated with a patent rotating furnace that he could manufacture iron from the ironsand of Canada, producing iron balls in four hours, which were then treated in the open-hearth furnace and converted into mild steel. At that time his process was tried in Pittsburgh, but unfortunately it did not prove a commercial success, on account of cost.

    Mr. John Chambers visited the Philadelphia Exhibition in 1876, and there tried to induce men in the iron and steel trade to test the ironsand; but nothing could be arranged, as all the ironmasters of America were fully occupied in building additional works to handle the trade which they could

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    easily get in America for all the iron that could be produced from ordinary iron-ore at a cheap rate. But before leaving New York Mr. Chambers heard that Mr. Joel Wilson, of Dover, New Jersey, had in 1873 patented a furnace which he claimed would treat ironsand and convert it directly into wrought iron; but everything was in an embryo state, and it was arranged for an agent to watch the work of Mr. Wilson, who claimed in 1882 to be able to manufacture successfully from sand. Mr. Guy H. Gardner, of New York, obtained an option on the New Zealand patents, purchasing them jointly with Mr. Chambers; and so sanguine was the inventor that he agreed to send out his best man, Mr. W. H. Jones, to demonstrate the working of his patent in New Zealand.

    A full-size furnace was erected in 1882 to manufacture 3 tons of iron per day. The furnace was built from a drawing accompanying patent specifications granted to R. L. Malcolm (J. Wilson)* and G. H. Gardner, except that the reducing-furnace contained eight retorts, instead of sixteen as shown on the drawing accompanying Malcolm's patent. The drawing of the furnace as built has been reconstructed and shown in the figure accompanying this paper. It consisted of a deoxidizer, A, and of an ordinary reverberatory or open-hearth furnace, about 17 ft. long, divided into three compartments—B, the balling-furnace; C, the puddling-furnace; D, the firegrate. The coal used for firing on the ordinary furnace-bars was from Westport and Newcastle. The hot gases from the furnace played direct on the floor of the puddling-furnace C, passed on to the balling-furnace B, then passed through the roof into a central flue F, about 2 ft. in diameter, and were carried up the full length of the deoxidizer, a height of 21 ft.; the gases struck the crown at the top of the furnace, and passed in a downward direction between the retorts R, there being radial spaces F between the retorts for the gases to pass through; on reaching the bottom they were deflected so as to pass upwards (F) on the periphery or outside of the surface of retorts, and between that and a firebrick lining against the shell of furnace. On the gases reaching somewhere near the top they passed out into an annular flue and by way of an iron chimney into the atmosphere.

    The deoxidizer held 10 tons of carbon and ironsand. After the silica had been extracted by a magnetic separator it was thoroughly mixed with 20 per cent. to 25 per cent. of coal or charcoal, Taupiri coal being used. The material was hoisted to a platform above the deoxidizer, from which each retort was filled from filling-boxes. It required twenty hours to deoxidize or carbonize the iron by driving out the oxygen. The sand was red-hot, but not so sticky that it would not run through the chutes leading to the balling-furnace, which were controlled by heavy gate-valves.

    The deoxidized sand dropped on to the floor of the balling-furnace, where it lay for some thirty minutes, there being a door at the side of the furnace to permit the puddlers to test the condition of the material before balling it. It would work up exactly as cream works into butter, having very much the same appearance. On a ball of about 18 in. diameter being made it was rolled or passed over to the puddling-furnace C, when it was again attacked by a fresh set of puddlers, who vigorously worked it up

    [Footnote] * “Malcolm, R. L.—8th January, 1883—Improvements in furnaces for reducing iron-ores,” N.Z. Pat. Reg. No. 762.

    [Footnote] † “Gardner, G. H.—23rd April, 1883—Improvements in furnaces for the manufacture of bar iron and blooms,” N.Z. Pat. Reg. No. 818.

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    until it was ready for the squeezer; or, in the case of the first trials, the ball was placed on the anvil of a steam-hammer and gently squeezed into a square form, after which it could be hammered with the full force of the hammer and drawn into the shape of a billet or bloom.

    Picture icon

    Design of Furnace.
    A, deoxidizer; B, balling-furnace; C, puddling-furnace; D, fire-grate; F, flues; R, retorts.

    The cost of the first furnace was £500. It was completed early in February, 1883, and on the 27th the first iron by the new process was made into billets, and it was shown that the quality exceeded all expectations. On the 5th March George Fraser and Sons, Auckland, made three bars, 8 ft. long, 2 in. square, of perfect quality. The furnace, under the charge of W. H. Jones, was kept working for about ten days, and at that time good blooms were produced, which were worked up into bars and thoroughly tested by several leading blacksmiths in Auckland, Mr. George

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    Leahy making a large double pair of ornamental gates of beautiful design to demonstrate the quality of the iron, which was equal to Netherton Crown.

    After a stoppage for some necessary repairs the fires were lit for a second time. The best results obtained from one charge in the deoxidizer was the manufacture of 6,751 lb. of iron from 14,625 lb. of sand; the slag or cinder amounted to 7,215 lb., the loss of cinder and waste in furnace being reckoned at 659 lb., resulting in 46 ¼ per cent. of iron being produced from the separated sand. The operations were carefully watched by Messrs. James Stewart and Edmund W. Otway, of Auckland, who on the 29th March made the following report:—

    “We have the honour to state that, as requested by you, we have attended at your works erected at Onehunga for the reduction of the ironsand, for the purpose of examining in detail the whole process and obtaining data for reporting on the cost of production. We are as yet unable to make a complete report, but hasten to give you a few of the more important results, and the deductions which may fairly be drawn from them. We hope shortly to report in a more exhaustive manner.

    “On Monday, the 19th instant, four retorts were filled with a mixture of ironsand and charcoal, in the proportions of one measure of sand to two of charcoal. Other four retorts were filled with a mixture of ironsand and ground Waikato coal, in the proportions of two measures of coal to three of sand, the intention being to put in 20 per cent. by weight of both charcoal and coal in proportion to the sand. The above mixtures give that percentage of coal, but more than that of charcoal, and in subsequent operations in filling up the exact ratio of 20 per cent, was adhered to.

    “The fires were lighted on Monday night, and on Wednesday a small charge was tried, but found not sufficiently carbonized or deoxidized—either term appears correct. Puddling was therefore deferred until Thursday, the 22nd, and was then commenced with the coal mixture principally. But it soon became apparent that the coal was not in sufficient proportion to carbonize the ore, and after working all day with a very poor result it was determined to discharge all the coal mixture remaining in the retorts and recharge with charcoal and ore.

    “On Friday work was resumed with better success, but, as coal mixture had been used to fill up the shrinkage in the retorts remaining to be worked, its presence still caused trouble, principally by the great amount of slag produced, and iron dry and difficult to work to nature, causing the blooms to be returned to the furnace once, and sometimes twice.

    “On Saturday the work went on very well, and if the draught of the furnace had been perfect little could have been desired in the result.

    “We have worked out the result in two ways: (1) total sand ore worked by both mixtures, against total yield of iron; (2) discarding the yield of iron on Thursday, when the iron-ore was mixed with the coal, as obviously the fairest view to take. The first result is 38 cwt. of iron from 149 cwt. of sand, equal to 25.5 per cent. (very nearly) of puddled blooms. The second view gives 33.25 cwt. from 98 cwt. of ore, equal to 34 per cent. (nearly) of puddled blooms.

    “From the somewhat extemporized nature of the works, we feel confident that the above percentage at least can be maintained by carbonizing with charcoal. And by increasing the coal mixture to an amount equivalent to 20 per cent. of carbon we have reason to believe a like result will be obtained.

    “Discarding Thursday's run, the coal used in puddling and keeping up the heat at night on Friday, Saturday, and Monday, including the coal

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    necessary to keep the furnace hot over Sunday, was 3.21 tons, which works out to 38.6 cwt. per ton of blooms. We feel quite safe in saying that with continuous working the conversion of the ore can be effected at under 30 cwt. of coal per ton of iron, and that all the heat and firing required by the whole process can be supplied by the waste heat from the furnace and retorts in the use of that weight of coal. This is even with the direct use of coal; but with the most improved gas regenerative furnace not only will the amount of coal be very largely reduced, but much inferior fuel may be used.

    “Keeping in view all the above points, we have no hesitation in saying that the process has been shown to be profitable, but to what extent we are yet unable to say. We trust, however, that this interim report will be of service to you.”

    It was estimated the cost of manufacture would be as follows:—

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    Cost of 3 tons of ironsand at works, at 6s. 8d. per ton £ s. d.
    1 0 0
    30 cwt. coal at works 1 10 0
    Carbon for retorts 0 10 0
    Puddling, per ton 1 0 0
    Shingling, rolling into puddle-bars, weighing, shearing, piling, reheating, and rolling into 1 in. bars 0 10 0
    Engine-driver's time, millwright, bricklayers, & c., and incidental expenses 0 10 0
    £5 0 0
    Add 25 per cent. for establishment charges, depreciation on plant 1 5 0
    Cost per ton £6 5 0

    When the furnace was working during April the works were visited by Mr. Pearson, of Pearson, Knowles, and Co., of Warrington, who took a great interest in the work, and said the process represented the greatest advance of the present age. At the same time they had another distinguished visitor—Mr. Sydney Gilchrist Thomas, of London, inventor of the basic process which did so much to cheapen the cost of manufacturing steel. He declared that for the first time he had seen wrought iron made direct from ore, and it was what all ironmasters had been trying to do for a century. He was prepared and wished to enter into a contract for the purchase of 5,000 tons of blooms per annum.

    As a result of the visits of these two men and the favourable reports obtained from all quarters it was resolved to form a company with a capital of £200,000, made up of 40,000 £5 shares: of these, 9,103 were subscribed by the public, leaving a balance of 30,897; the paid-up capital being £45,515. The total expenditure was about £58,000, the plant and buildings costing £34,329.

    The company proposed to order sufficient material and plant for the erection of ten deoxidizers and furnaces. A rolling plant was ordered from Messrs. Walker, Eaton, and Co., of Sheffield, who supplied an 18 in. forgetrain with squeezer, pendulum shears, and engines, a 14 in. and 10 in. merchant mill, hot-saw, two shingling-hammers (each of 50 cwt.), and all necessary gear for a complete works to turn out 30 cwt. of bar iron or rolls per day. Four Lancashire boilers and four Wilson gas-producers were

    – 228 –

    ordered from Tangyes Limited, to provide gas for heating furnaces, firing boilers, & c., it not being proposed to use coal in any furnace or place.

    The site on which the experimental furnace was erected was purchased, consisting of about 5 acres on the south-east side of the Onehunga railway-station, from which a siding was run into the works. It had a water frontage, which became valuable by a canal being cut to deep water to enable vessels of light draught to come right into the works, so that Westport or Newcastle coal could be delivered direct. It was a fine site, having many advantages, several springs providing a good supply of fresh water. It was admirably situated for cheap and economical working, for it was intended that the ironsand should be brought from the North Head of Manukau Heads, where a Government lease, of sixty-six years, was obtained for 6 ¼ miles of beach and 1,000 acres of land, on which there were millions of tons of iron. There was good shelter and deep water at the Heads for loading, it being proved from actual experience that the sand could be raised, trucked, delivered to vessel, and conveyed to works at a cost not exceeding 6s. 8d. per ton. The average sample of ironsand obtained from the Manukau Heads would analyse as follows:—

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    Iron-oxide 88.88
    Titanium 0.30
    Lime Trace
    Magnesia " Silica 9.98
    Loss 0.84
    Equal to 66.36 per cent. iron.

    The patience of the shareholders was somewhat tried by the long wait for machinery to come from Great Britain. Contracts were let for a furnace-house to contain the forge-train, which measured 106 ft. by 100 ft. The roof of this building had a single span. There was also a similar building, 100 ft. square, for the merchant mills and reheating furnaces. Offices, laboratory, carpenters' and engineers' workshops, foundry complete with cupola, set of furnaces for making crucible steel, storage, drying and mixing shed for coal and sand, were all got under way, and, in addition, a brickkiln, which turned out 200,000 firebricks before the machinery arrived.

    The prospects were bright and every one was sanguine of success; but on the 23rd December the company suffered a great blow by Mr. W. H. Jones quarrelling with a bricklayer, whom an hour or two afterwards he shot in the main street of Onehunga, for which he got ten years' hard labour. No suitable man could be obtained from America, and it was thought that Mr. Edmund Otway, an old ironmaster, would fill the position, which he did for some months. He was a very capable man, but unfortunately he broke down and died in June, 1884. This was looked upon as a serious loss, but fortunately the position was filled by Mr. John Heskett, at one time manager of one of Bolckow Vaughan's works at Middlesborough, who proved to be thoroughly capable, and manfully carried on the work. He, unfortunately, had to fight against great difficulties through ill health, and finally broke down at a critical time, when the works were completed and ready to commence operations.

    On the 7th November, 1884, the first machinery arrived from England; it was quickly erected, for by the 1st May, 1885, the fires were lit in two furnaces, when it was shown that 1 ton of bars could be made from 3 tons

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    of 75 per cent. oxide—that is, the sand as found on the beaches. The new furnaces were supplied by gas under forced draught generated by the four Wilson gas-producers, and all worked well for a few days, when it was found that the coal contained too much moisture, which destroyed the heating properties of the gases. Again and again endeavours were made to overcome this difficulty. The fires would be lit in the gas-producers, and the quality of gas for the first few hours would be perfect; but as the furnaces became hot and just about ready for men to work the sand and deoxidizers the heat gradually fell away, or a series of explosions took place, which showed it was time to stop. This was one of the first difficulties met with, and one that was never overcome in spite of many experiments.

    By this time the shareholders were becoming impatient, for they wanted to see returns. The loss of two managers, followed by the enforced retirement of Mr. John Heskett, had a good deal to do with the company breaking up.

    Mr. James McAndrew, an ironmaster, who had been on the Clyde, accepted the position of manager, and did his best to produce iron from sand, but none of Mr. W. H. Jones's successors could produce iron of the same quality as he did. There were difficulties with the deoxidizers: air seemed to leak through or get into the retorts, resulting in a portion of the sand not being deoxidized, and, although it would work up into a bloom which had the appearance of being good, when passed through the forge-rolls the bars would fracture through the sand not being properly deoxidized or cemented together.

    The directors got a rude awakening by receiving a report from Mr. John Coom, which showed that the iron was brittle and could not be sold as a first-class commercial article. The report reads as follows:—

    “The iron was tested for tensile strength and by bending; the steel was made into tools and used in wheel-turning and general work.

    Three pieces of the iron (marked ‘A’ in the schedule) were drawn down to a sectional area of ¼ in.; the two pieces marked ‘B’ were tested as sent from the works, the section of these being about 1 square inch.

    “The apparatus used in testing is not one specially designed for the purpose: the results cannot, therefore, be looked upon as strictly accurate.

    “For your information I have shown results of some of Kirkaldy's tests of Bowling and Lowmoor iron, and the specification of the iron supplied for the Ohio (America) railroad bridge.

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    No. of Piece. Brand. Mean Breaking-weight per Square Inch of Original Section. Contraction of Area at Fracture. Mean Elongation.
    Tons. Per Cent. Per Cent.
    1 A 26.00 23.4 7.3
    2 A 26.46 25.1 4.1
    3 A 31.93 27.6 10.9
    4 B 16.26 20.6 8.5
    5 B 16.26 4.5 2.7
    Bowling 27.86 45.3 29.4
    Lowmoor 27.59 53.1 26.5
    Ohio River Bridge specification 26.75 25.0 15.0
    – 230 –

    “The pieces 1, 2, and 3, which were drawn down from a large section, are superior to the pieces 4 and 5, which were tested in same section as received.

    “The results show the iron to be of a hard and unyielding character, but it evidently is improved by working; it would require this before it could be safely used in engineering-works. The mean breaking-weight is high, but the contraction at the fractured area and the elongation are low, showing the iron to be as I state.

    “A farther test of the iron was made by bending cold, and the results were fairly good: two pieces were bent double and showed but few cracks.

    “The steel was made into tools for use in the wheel and other lathes; these were given to the turners with instructions to use them for a week and then report. Their report was very favourable: they say the tools stood as well as most of those made from the imported article.”

    The company then resorted to manufacturing wrought iron from scrap, but this was not profitable. First-class chemists were engaged in the laboratory, Mr. D. S. Galbraith working very hard in the hope of overcoming difficulties, but this was never done.

    The company struggled on until November, 1886, when, with its capital spent and a liability of £20,000, an attempt was made to reconstruct; but the shareholders would not find money, and the assets of the company were taken over by the mortgagee. For a short time it was worked under tribute in the manufacture of bar iron from scrap, but this was never profitable, and finally the plant was broken up and shipped to China, to be used there in new ironworks.

    So ended the most serious attempt at manufacturing iron from the sands of New Zealand, and one wonders now why it was not a success. Everything was done that could be thought of at the time by all concerned, for they were sanguine to the last, and hoped to retrieve the fortune spent in endeavouring to create a great industry for the Dominion.

    Art. XXV.—Notes on the Autecology of certain Plants of the Peridotite Belt, Nelson: Part I—Structure of some of the Plants (No. 1).

    [Read before the Otago Institute, 9th October, 1917: received by Editors, 29th December, 1917; issued separately, 24th June, 1918.]

    Introduction.

    At a short distance from the city of Nelson there is an area known as the “Mineral Belt.” This is a zone of boulder-strewn land-surface, often dun-coloured in appearance, underlain by peridotite and serpentine rocks, which extends from D'Urville Island, in Cook Strait, south-west for a distance of sixty miles. It is an almost continuous band, but it disappears for about a mile between the valleys of the Lee and Serpentine Rivers. At its narrowest part the Mineral Belt is 100 yards wide, and it reaches its maximum width of 3 miles 50 chains in the vicinity of the Dun Mountain. The area occupied by the Mineral Belt is about 29 ½ square miles.*

    [Footnote] * J. M. Bell, E. de C. Clarke, and P. Marshall, The Dun Mountain Subdivision, N.Z. Geol. Surv. Bull. No. 12, 1911.

    – 231 –

    The vegetation of the Mineral Belt presents a striking contrast with that of the neighbouring land-surface, which is clothed with luxuriant forests of southern-beech (Nothofagus spp.). On the Mineral Belt there are three principal plant-associations:—

    1.

    Shrubland.—This is usually found near the margin of the Belt, and is composed of many species that are found in the adjacent forests, but on the Belt they are much dwarfed—e.g., Griselinia littoralis is usually a tree 10–16 metres high, but in the shrub formation on the Mineral Belt it is reduced to a woody shrub ⅓—2 metres high; Nothofagus fusca, a forest-tree, is represented by small trees 2–3 metres high. In addition to these dwarfed representatives of the neighbouring forests there are in this association a number of shrubs which are not reduced. Such plants are Cassinia Vauvilliersii var., Coprosma propinqua, Dracophyllum longifolium var., and Leptospermum scoparium var. In this association there are a number of small herbs—e.g., Claytonia australasica, Colobanthus quitensis, and Epilobium pedunculare var.

    2.

    Open Scrubland.—In this association the most characteristic plants are Cassinia Vauvilliersii var., Dracophyllum rosmarinifolium, Exocarpus Bidwillii Hymenanthera dentata var. alpina, Veronica buxifolia var., V. Menziesii var., V. pinguifolia (?), Pimelea Sutern, and Muehlenbeckia axillaris. Among the herbs to be found in this association are Myosotis Monroi, Notothlaspi australe, Gentiana corymbifera, Anisotome aromatica, and A. filifolium.

    3.

    Tussock Grassland.—The dominant plant is Danthonia Raoulii var.; sub-dominant are Phormium Cookianum and Astelia montana var.

    It is proposed to describe the anatomy of a number of the plants of the Mineral Belt in a series of short papers, and then the results obtained from these investigations will be considered.

    In addition to the anatomy of the leaf and of the stem of the different species, a brief description of the growth-form of the plant is given. In those cases where the usual form of the species is found on the Mineral Belt this description is quoted from Cheeseman's Manual of the New Zealand Flora (1906). Where the species is modified in form, a description of the usual type is quoted, and then that of the plant as it is found on the Mineral Belt is given.

    1. Nothofagus fusca Oerst.

    Usual Growth-form.—“A noble forest-tree 60–100 ft. high; trunk 4–8 ft. diam.; bark dark-brown or black in old plants, deeply furrowed, smooth and greyish-white on young trees; branchlets and petioles pubescent. Leaves evergreen, petiolate, ¾–1 ½ in. long, broadly ovate or ovate-oblong, obtuse or rarely acute, cuneate at the base, rather thin but firm, pubescent above and glandular beneath when young, glabrous when old, deeply and sharply serrate, veins conspicuous; stipules linear-oblong, caducous.”

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    Mineral Belt Growth-form.—A small tree 6–8 ft. high, with leaves ½–¾ in. long.

    Anatomy.

    Leaf.—The upper epidermis consists of small cells, more or less oval in transverse section. The cell-walls are thin, except the external walls, which are slightly thickened and also cuticularized. Some of the epidermal cells, in the vicinity of the vascular bundles, are produced into long unicellular hairs which have thin, slightly cutinized walls. There are no stomates on the upper surface.

    The lower epidermal cells are small, oval, and thin-walled, the external walls being slightly thickened. A thin cuticle is present. Stomates are

    – 232 –

    confined to the lower surface; the guard-cells are small and on the same level as the other epidermal cells, the stoma being protected by guard-cell ridges. On the lower surface there are hydathodes, which are sunk in slight depressions.

    The chlorenchyma is differentiated into palisade and spongy tissue. The former consists of 3 rows of thin-walled cells, the outer layer with the cells very closely arranged so that there are no intercellular spaces; the 2 inner layers are arranged more loosely. The spongy tissue consists of small thin-walled irregular cells which have rather small air-spaces between them. Many of the chlorenchymatous cells contain tannin.

    The midrib is slightly prominent. Surrounding the vascular bundle of the matous there is a sheath 1–3 cells thick, consisting of small sclerenchy-matous cells. Around this there is a sheath of larger cells, also with lignified walls. The xylem consists of vessels of moderately large diameter and of wood-fibres. Above the xylem there is a small amount of parenchyma. The phloem is in the form of a crescent; the parenchymatous elements contain tannin.

    Stem.—The cork is a fairly wide band of tissue, consisting of small, very compact cells.

    The cortical cells are large, and oval in transverse section. These cells are thick-walled, and many of them contain tannin. They are closely arranged, so that there are only small intercellular air-spaces.

    The pericycle fibres form a wide band, in which the cells vary considerably in size in transverse section. Some are small, with their cell-walls so much lignified and thickened that the lumen is almost obliterated; connecting groups of these cells are much larger cells, also with thickened, lignified walls, but the cell-cavities are large.

    The phloem forms a narrow band, and the parenchyma contains tannin. The spring wood consists of a large number of vessels of large diameter, together with wood-fibres. The autumn wood is formed of much smaller vessels, and of wood-fibres in which the lumen is almost obliterated.

    The medullary rays are uniseriate, and the cells have thickened lignified walls, and contain tannin. The pith cells are large and round, have thickened lignified walls, and contain abundant starch.

    2. Nothofagus cliffortioides Oerst.

    Usual Growth-form.—“A small tree, usually from 20 ft. to 40 ft. high, rarely more, with a trunk 1–2 ft. diam., in alpine localities often dwarfed inter a much-branched bush 5–12 ft. high. Branches spreading, often distichous, especially in young trees; branchlets densely pubescent. Leaves shortly petiolate, distichous, ⅙–⅔ in. long, ovate-oblong or ovate or ovateorbicular, acute or subacute, rarely obtuse, always broadest at the unequally rounded or almost cordate base, quite entire, very coriaceous, glabrous and reticulated above, more or less clothed with greyish-white appressed hairs beneath, margins thickened, often recurved; stipules membranous, caducous.”

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    Mineral Belt Growth-form.—A much-branched bush 4–8 ft. high, with leaves ⅙–¼ in. long.

    Anatomy.

    Leaf.— The upper epidermis consists of small cells which are more or less square in transverse section. These have their cell-walls thickened, and there is a thick cuticle. Some of the epidermal cells contain tannin. On the upper surface there are numerous glands which are formed from epidermal cells.

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    The palisade and the spongy parenchyma, the lower epidermis, and the stomates are the same as in N. fusca, but on the lower surface some of the epidermal cells are produced into unicellular hairs, which have thin non-cutinized walls. There is a thick cuticle on the lower surface. Many of the mesophyll cells and the cells of both the lower and the upper epidermis contain tannin.

    The vascular bundles are the same as in N. fusca, but the midrib is smaller.

    Stem.—The structure is essentially the same as in N fusca, the only differences being—(1) There are more pericycle fibres; (2) the phloem forms a wider band; (3) the pith cells do not contain starch; (4) there are more numerous vessels of large diameter.

    3. Exocarpus Bidwillii Hook. f.

    Growth-form.— “A small much branched rigid procumbent shrub 6–24 in. high, branches ascending, short, stiff, terete, deeply furrowed. Leaves reduced to minute triangular scales, alternate, persistent,”

    Picture icon

    Fig. 1.—Exocarputs Bidwifai, Portion of plant (½ natural size). aruit; b, loaves reduced to triangular scales.

    A portion of the plant is shown in fig. 21, which also shows, the fruit, which is seated on a thin kenlargede thickened red and succulent peduncle. The perianth-segments are persistent under the fruit.

    Anatomy.

    Stem (figs. 24).—The structure of the stem is shown roughly in fig. 2. From this it will be seen that the furrow stiff hairs, that there is a thick cucculte & c. The more detailed slructure of the stem is shown in fig. 4.

    The epidermis consists of small squarish cells with thin cell-walls and an extremely thick cuticle. In the furrows the epidermal cells are larger and there is only a thin cuticle. Many of the epidermal cells in the furrows are produced into stiff hairs, which have thick walls which are cuticularized. In the furrpws are the stomates, but these cannot be seen well in transverse section. as their long axes are placed transversely to the surface of the” stem.

    – 234 –

    Fig. 3 gives the epidermis from a longitudinal section; from this it will be seen that the stomates are at the same level as the epidermal cells, and the opening is protected by guard-cell ridges.

    The cortex is composed of closely packed more or less polygonal cells with thin walls. In the outer part of the cortex, and especially in the

    Picture icon

    Fig. 2.—Excarpus Bidwhi. Diagrammatic transverse section of the stem (x 24). a, thick cuticle: b, furrow lined with hairs; c, pericycle fibres.
    Fig. 3.—Exocarpus Bidwillii. Longitudinal section through epidermis (X 350). a, guard-cell ridge.
    Fig. 4.—Exocarpus Bidwillii. Transverse section of stem (x 120). a, thick cuticle; b, tannin-containing cells; c, chlorenchyma; d, pericycle fibres; er phloem vessels of xyiem; g, hgnified pith.

    ridges, the cortical cells containtannin; in the inner part of the cortex most of the cells contain numerous chloroplasts, but some contain tannin. At intervals there are large groups of pericycle fibres, composed of small cells with very thick lignified was and small lumen.

    – 235 –

    The phloem forms a wide band in which the elements are very regularly arranged. Most of the parenchymatous cells of the phloem contain tannin. The xylem consists chiefly of wood-fibres of small diameter; these have very thick walls and small lumen. The number of vessels is small in comparison with the amount of wood, and they are not of wide diameter. The medullary rays are numerous and uniseriate; the cells have lignified walls, and contain tannin. The pith is solid, and consists of polygonal or roundish cells with pitted lignified walls.

    4. Muehlenbeckia axillaris Walp.

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    Growth-form” A small much-branched prostrate or diffuse shrubby plant, usually forming densely matted patches 3–12 in. diam., but sometimes open and straggling; stems and branches woody; branchlets puberulous. Leaves on rather long petioles, small, 1/10–⅓ in. long, broadly oblong or ovate-oblong or almost orbicular, obtuse or retuse, rounded at the base, flat, quite glabrous, dotted beneath.”

    Anatomy.

    Leaf.—The upper epidermis consists of large cells with thin walls, except the external ones, which are slightly thicker. There is a very thin cuticle. The epidermal cells form mucilage-sacs. The lower epidermis is similar to the upper. A few stomates are found on the upper surface, but they are much more numerous on the lower surface; the guard-cells are small and are level with the other epidermal cells. On both surfaces of the leaf there are hydathodes, which are sunk in small depressions; they are more numerous on the lower than on the upper surface.

    The chlorenchyma is differentiated into palisade and spongy tissue. The palisade tissue is found on both surfaces of the leaf; there are 3–4 layers of cells on each side. The cells are small, their walls are thin, and they contain numerous small chloroplasts. The outer layers contain tannin. The cells are closely packed, so that there are only very small intercellular air-spaces. The spongy tissue consists of fairly large cells with thin walls and containing numerous small chloroplasts. The air-spaces in this tissue are larger, and some of the cells contain tannin.

    The vascular bundles are frequent, but of small size. Above the xylem there is some stereome, and above this small-celled parenchyma. There is also small-celled parenchyma below the phloem. Each vascular bundle is surrounded by a sheath of large parenchymatous cells, which contain tannin.

    Stem.—The cork forms a fairly wide zone of very small compact cells.

    The cortex consists of oval cells which are closely packed together, so that there are only very minute intercellular air-spaces. Most of the cells contain tannin.

    The pericycle fibres form a narrow, more or less continuous baud 1—2 cells wide. The cells are small, and have thick walls and small lumen. The phloem forms a wide band, in which the parenchymatous cells contain tannin. The xylem consists almost entirely of wood-fibres, but there are a few vessels of large diameter.

    The medullary rays are multiseriate and are very wide. They consist of small cells with thickened lignified walls, and they contain abundant large starch-grains.

    The pith consists of rounded or polygonal cells with thick lignified walls. They are closely packed together, and are full of large more or less polygonal starch-grains, and some contain tannin.

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    5. Claytonia australasica Hook. f.

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    Usual Growth-form.—“A perfectly glabrous tender and succulent usually matted plant, with slender creeping stems 1–6 in. long. Leaves very variable in size, ¼–1 ½ in. long, alternate or in distant pairs, narrow-linear or linear-spathulate, obtuse, dilated into broad membranous sheaths at the base.”

    Mineral Belt Growth-form.–In the Mineral Belt plants the leaves are ¼—-⅓ in. long.

    Anatomy.

    Leaf (figs. 5 and 6).—The upper and the lower epidermis are similar; the epidermal cells are large and have thickened walls. A very thin cuticle is present. Stomates are confined to the upper surface of the leaf.

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    Fig. 5.—Claytonia australasica. Diagrammatic view of leaf (X 40). a, palisade tissue; b, aqueous tissue.
    Fig. 6.—Claytoma australasica. Transverse section of leaf, passing through midrib (X 160). a, guard-cell ridge; b, palisade tissue; c, xylem; d, phloem; e, aqueous tissue.

    The guard-cells are at the same level as the other epidermal cells, and the opening is protected by guard-cell ridges. The cells of the epidermis contain a few small chloroplasts.

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    Fig. 7.—Claytonia australasica. Transverse section of prostrate stem (X 210). a, guard-cell ridge cuticle; b, chlorenchyma; c, starch-grains; d, endodermis; e, pericycle; f, phloem; g, xylem.
    Fig. 8.—Claytonia australasica. Transverse section of the outer part of setem; showing a stoma (x 210). a, guard-cell ridge.

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    The chlorenchyma is differentiated. The palisade tissue consists of about 5 layers of somewhat irregular cells. These cells are very large and are compactly arranged, so that there are only small intercellular air-spaces. The cells contain a large number of small c