Art. XL.—Further Notes on the Nativity of Polygonum aviculare, L., in New Zealand, in reply to Mr. Travers.
[Read before the Auckland Institute, 23rd December 1872.]
In the fourth volume of the Transactions I had occasion to point out the inaccurate and misleading character of the statement on which Mr. Travers based his opinion respecting the nativity of Polygonum aviculare, as expressed at page 336 of the third volume. I am now indebted to the courtesy of that gentleman for a copy of a paper (see Art. XXXIX.) read by him during the present session of the Wellington Philosophical Society, on which I am desirous of offering a few remarks.
Mr. Travers does not attempt any defence of the grounds upon which his theory was previously based, but still considers the plant to have been introduced, first, from the alleged absence of any reference to it by the earlier botanists, and secondly the possibility that seeds may have been brought amongst those of cultivated plants, or in other ways by the early missionaries, or by the whalers and trading vessels that visited the islands prior to the commencement of systematic settlement. The statements under the latter head occupy the chief portion of his paper, and may be dismissed with few words. Such a “possibility” h´s never been disputed, but is a very different matter from the real question at issue, and would have equal force if adduced to support the alleged introduction of other plants whose nativity has not yet been called in question.
To prevent misconception I quote the passages in Mr. Travers' paper respecting the absence of mention of this plant by the early botanists:—
“Now it would be somewhat singular that, if these plants (Polygonum aviculare and var. dryandri) really belonged to the indigenous flora, they should have been overlooked by Banks and Solander in 1769, by the Forsters and Dr. Sparrman in 1772, by Anderson in 1777, and by Menzies in 1791. I admit, however, that Anderson, whose collections were very limited, and Menzies, who devoted himself almost exclusively to the Cryptogamia, might have overlooked these plants, though the fact would still remain a singular one. * * * It´ is still more remarkable too that neither plant is mentioned by D'Urville, who collected in 1822, by Fraser in 1825, by Allan Cunningham in 1826, nor by Lesson in 1827,” (see p. 311).
The value to be attached to the argument based on the above statement depends upon the completeness and extent of the collection made by each botanist, and especially on their having included those plants common to Europe (particularly to the British Islands) and New Zealand. It is therefore desirable briefly to consider the number of species recorded by each in connection with the localities visited.
Banks and Solander, 1769.—These botanists examined a large number of rich and interesting localities between the “Bay of Islands and Otago, including the shores of Cook Strait.” The expedition spent five months in exploring the coast, and the number of flowering plants and ferns collected or recorded during its stay is larger than that of any other botanist named by Mr, Travers, yet it is under 380 species.
The Forsters and Dr. Sparrman, 1772.—Their collections were remarkably small, numbering only 160 species.
Anderson, 1777.—Dr. Hooker states that this collector obtained “very little indeed, and nothing of any importance.”
Menzies, 1791, devoted himself to the collection of mosses and Hepaticœ.
D'Urville, 1822, and Lesson, 1827, collected in the Bay of Islands, the Thames River, Cook Strait, and other rich botanical localities, yet their joint collections numbered only 200 species, which were described with 60 or 70 of the Forsters' plants by Professor Richard.
Fraser, 1825.—Dr. Hooker writes: “Mr. Charles Fraser, the Superintendent of the Sydney Botanical Gardens, landed for one day in the Bay of Islands, and made a small collection of dried plants. He, however, procured more living ones.”
Allan Cunningham, 1826.—After deducting the vast number of spurious species described by this energetic explorer the total number of plants collected by him will be found somewhat less than that of Banks and Solander.
Notwithstanding Mr. Travers' opinion on the singularity of no mention of the knot-grass having been made by Anderson and Menzies, I am sure that most observers will agree with me in considering that the extremely limited collection of the one, and the almost exclusive attention paid to Cryptogams by the other, afford excellent reasons for neither having made special mention of so common a plant. Neither could it be supposed that Fraser would have collected it during his single day's exploration at the Bay of Islands.
Leaving out of consideration, on account of their extremely fragmentary character, the small collection of 160 species made by the Forsters and Dr. Sparrman, by D'Urville and Lesson, of 200 species during two voyages, the very few. plants collected by Anderson, and the mere names (so far as Mr. Travers' views are concerned) of Menzies and Fraser, the only collections of any extent are those of Banks and Solander, and of Cunningham, As the remarks I shall have to make apply with almost equal force to each I shall confine myself more particularly to that of Banks and Solander.
As already stated the recorded number of species of phænogamic plants and ferns observed by these botanists is between 370 and 380, collected during five months in “Poverty Bay, Tegadoo, Tolaga, Opuragi, the Thames River, Bay of Islands, Queen Charlotte Sound, and Admiralty Bay,” Does
Mr. Travers wish it to be understood that the extreme number I have given (Dr. Hooker states “upwards of 360”) comprises all the plants actually seen by Banks and Solander in these varied and distant localities? If so I am sure that no botanist possessing a detailed knowledge of the distribution of New Zealand plants will be foun to agree with him. From personal knowledge of three of the localities visited by them I can state that a larger number of species might be collected in each during a single week than appears to have been recorded by them as obtained during the whole time spent on the coast of New Zealand, notwithstanding that some of the species which were common in 1772 are now comparatively rare. Making every allowance for the limited extent of their excursions into the interior, and guided by the preserved statements of the localities visited, and what we know of the nature of the habitats from the plants actually recorded as having been first observed by them, there can be no doubt that a minimum number of 600 species might have been collected by botanists in their position. Assuming, however, a much lower estimate, say 500 species, how very natural that so common and unattractive a plant as the knot-grass should have been one of those omitted.
In the comparatively small amount of attention which was paid to common and well known plants a century or even half a century ago by botanists in a similar position to Banks and Solander, and in the restricted facilities then to be obtained for preserving plants on board ship, may be found fully sufficient reason for no mention being made of so common a plant as the knot-grass, or for no specimen of it having been preserved.
And not to mention the omission of certain endemic plants, common in several of the localities visited by them, I might say amongst the commonest, this view of the case is confirmed by the fact that other plants common to the British Islands and New Zealand are omitted from their collections, although no botanist would for a moment imagine on that account that they were not observed. Juncus maritimus is abundant all round the coasts of New Zealand, It is especially plentiful at the Bay of Islands, Thames River, Mercury Bay, Bay of Plenty, Poverty Bay, and Queen Charlotte Sound—all localities visited by the first expedition, and at some of which a protracted stay was made—yet no mention is made of it, although it could not possibly have escaped observation. Juncus bufonius appears to have escaped record by all botanists down to the time of Sinclair and Colenso, and affords in many respects a close parallel to its frequent associate the knot-grass; it occurs throughout the islands in dry and moist places, is especially abundant by road sides, although rarely absent from swampy places; in neglected cultivations it sometimes exhibits great luxuriance, and ascends the Southern Alps to a considerable altitude, In the northern part of the colony, and probably
throughout, it resembles Dichelachne crinita, D. sciurea, and other unquestioned natives, in having increased largely during the last eight or ten years, and often exhibits a luxuriance surpassing anything to be seen in the British Islands, even in Ireland where its climatal advantages most nearly resemble those of this colony; yet its nativity is, unquestioned, and there exists not the slightest ground for disputing it. A third species of this genus common to both countries was noticed by Banks and Solander, apparently on account of some slight differences having led them to consider it distinct. Lemma minor is another common European plant which often covers pools and quiet places on the margins of rivers and lakes, and open water in swamps, with a mantle of green, and in these islands is found from the North Gape to Otago, from the central lakes to the sea; yet this also was not mentioned by the earlier botanists; so also Sparganium simplex, a common paludal plant in the north, and probably in the south also. Are these and others to be considered introduced on the ground that they were first mentioned by Bidwill or later botanists, or on the possibility that the seeds of some of them might have been brought in various accidental ways?
Zostera marina is a plant the seeds of which could not possibly have been introduced. It is plentiful in the Bay of Islands, Thames River, Mercury Bay, Bay of Plenty, Cook Strait, and in fact all round the coasts where the requisite conditions for its growth exist; it is frequently found floating at a considerable distance from the shore, yet the first positive record of its belonging to the New Zealand flora occurs in the second part of the “Handbook,” which is scarcely six years old. Is it to be considered introduced on this ground? Yet it is far more improbable that this plant should have escaped notice than the knot-grass.
It would be easy to place the trivial value of Mr. Travers' argument in a still more forcible light, but it will be sufficient to remark that taking it in its most plausible form it would have no value in the estimation of a botanist well acquainted with the history of botanical discovery, and especially of one possessed of a precise knowledge of the plants actually collected by the earlier botanists.
In writing the above I have tacitly adopted Mr. Travers' assumption that the knot-grass is not mentioned by the earlier collectors in New Zealand, but is this correct? I commend the following extract from Mr. Anderson's remarks on the plants observed by him at Queen Charlotte Sound to the special attention of Mr. Travers. It will be found at page 148 of the first volume of “Cook's Third Voyage,” in the well known quarto edition of 1784:—
“Amongst the known kinds of plants met with here, are common and rough bindweed; nightshade and nettles, both which grow to the size of small
trees; a shrubby speedwell, found near all the beaches; sow-thistles, virgin's bower, vanellæ, French willow, euphorbia, and crane's-bill: also cudweed, rushes, bull-rushes, flax, all-heal, American nightshade, knot-grass, brambles, eye-bright, and groundsel, but the species of each are different from any we have in Europe. There is also polypody, spleenwort, and about twenty other different sorts of ferns, entirely peculiar to the place; with several sorts of mosses, either rare, or produced only here; besides a great number of other plants, whose uses are not yet known, and subjects fit only for botanical books.”
I admit that at first sight the saving clause, “the species of each are different from any we have in Europe,” appears to shut out the probability of Polygonum aviculare being the plant intended, but upon examining the statement I find that several species are identical not only with continental European plants, but with common plants of the British Islands, and this beyond the possibility of dispute: thus the bindweeds are Convolvolus soldanella, and C. sepium, the sow-thistles Sonchus asper, the bulrushes Scirpus lacustris and Typha latifolia, the American nightshade Solanum nigrum; still further the rushes might have included Juncus effusus (J. tenax, b., Banks and Sol.), and possibly two other forms common to both countries; so also the crane's-bill and cudweed, although as these are open to question I merely state the possibility. But to what New Zealand plant except Polygonum aviculare could the English name of “knot-grass” be applied? Certainly not to any of its close allies, Polygonum decipiens would have been called a Persicaria, certainly not to the shrubby climbing plants which we now call Muhlenbeckias, and which Anderson would have at once separated from knotgrasses, independently of the restricted use of the term by English botanists in all times, by their fruticose, climbing habit, fleshy, shining perianths and polygamous flowers (the small species of this section, M. axillaris and M. ephedroides, were unknown till discovered by Colenso). Rumex is out of the question. I feel confident that any botanist qualified to form an opinion by possessing a good knowledge of the floras of New Zealand and the British Islands will confirm me in stating that with the exception of Polygonum aviculare there is no member of the New Zealand flora to which the term “knot-grass” would have been applied by a British botanist of the last century. I do not, however, urge this point, as it seems not impossible to obtain direct evidence on this interesting subject.
To several of the statements made by Mr. Travers exception may fairly be taken. It is, however, only worth while to allude to one, in which he states “the plant is always associated with the immediate occupation of land by man, making its habitation either in places which he has disturbed and then suffered to lie waste, or along the sides of the tracks which he makes over virgin
country.” This is highly inaccurate and misleading. I have already stated that in the North Island the plant exists under the same circumstances as those which surround it in the British Islands, manifesting a decided preference for cultivated land, but found also in widely different situations, on mountains and in forests. When the Thames gold-field was first opened, before tracks had been made to any great extent, it was to be seen sparingly in the wildest and most untrodden spots up to 1,900 feet, exactly under similar circumstances to those under which it occurs in the centre of the island, where I had the pleasure of collecting it last summer, and I may state that I have received specimens of the var. dryandri, collected with Veronica, tetragona and other sub-alpine plants on the all but untrodden slopes of Ruapehu and Tongariro by my valued friend, Captain Gilbert Mair.
Mr. Travers' opinion respecting the introduction of Azolla rubra will not be generally accepted unless supported by stronger evidence. I shall peruse with interest anything he can offer in support of his theory.