Art. XLII.—On the New Zealand Species of Ceramiaceæ.
[Read before the Philosophical Institute of Canterbury, 2nd November, 1904.]
Since the publication of the “Handbook of the New Zealand Flora” in 1864, the work done upon the New Zealand species of seaweeds has been scattered through scientific books and journals appearing in Sweden, Germany, France, and England. It is my object in this paper to give short diagnostic descriptions of all the species of the family Ceramiaceæ found in New Zealand, thus enabling the New Zealand student to determine without unnecessary difficulty the name of any species he may find. A bibliography of the subject will be found as an appendix to Part II. of this paper. I have clearly indicated what organs of reproduction are known, so that any future worker will be able at once to recognise whether any that he may find have been hitherto described or not. The family Ceramiaceæ in New Zealand is moderately well known, but still presents many difficulties to the investigator, the lack of type specimens in our museums often proving an insuperable bar to absolute certainty of identification. I have chiefly followed Engler and Prantl's “Pflanzenfamilien” in the description of the genera, and the accounts of some of the species are based upon the “Epicrisis Floridearum” of J. G. Agardh; but in most cases I have had specimens of my own,* from an examination of which I have been able to give descriptions that are often to a large extent new. I have presented to the Canterbury Museum examples of such species as were procurable and not already represented in it. It is too much to hope, in the absence of type specimens, that my identifications of Harvey's species have in all cases been successful, but I trust that my descriptions are at
[Footnote] * I have to thank Mr. J. Crosby Smith, of Invercargill, for generously placing at my disposition his large collection of Ceramiaceæ from southern Otago.
least sufficiently full and accurate to enable any subsequent investigator to determine what plant I have had under investigation.
The cell-dimensions given were obtained from specimens mounted in glycerine jelly, and variously prepared. They may therefore differ from those that would have been obtained from the measurement of fresh specimens. They should, however, at least be relatively correct.
The thallus consists of single branched cell filaments, sometimes with an adventitious cortex formed of rhizoids. This false cortex is produced in the genera allied to Callithamnion by the outgrowth of the rhizoids from the basal cell of lateral branches. In Ceramium and its immediate allies such filaments spring from the upper ends of the cells of the thallus, thus forming a peripheral crown of cells covering the place where the parent cell is joined to the one above it. In some cases the filaments clothe the main cell row, in others they fail to meet, and leave the intervening parts bare. The sporangia are solitary or distributed in groups over the thallus, or confined to special branches, either placed externally on the thallus or hidden in the cortex. The tetraspores are generally in tetrads, but sometimes variously divided. The antheridia are distributed in very varied form over the thallus, and contain generally many tightly packed spermatangia. The carpogonia bearing branches and those bearing the auxiliary cells are generally united in special procarps of various arrangement. The cystocarps are, as a rule, scattered over the upper part of the thallus, or more or less deeply sunk or completely buried in the cortex. The gonimoblasts (of which there are usually two in each cystocarp) form successively several lobes, of which nearly all the cells give rise to spores. The cystocarp if external is entirely naked, or covered only by an involucre of short incurved branchlets.
Key to the New Zealand Genera.
The branches of the thallus consisting of single rows of cells.
Spermothamnteæ.—Thallus naked or provided with very delicate verticillate ramuli.* Cystocarps terminal on special fertile branches. The fruit-mass of 1 or 2 gonimolobes.
Thallus with creeping rhizoids and upright laterally branched fertile shoots. Fruit-mass with 2 gonimoblasts 1. Spermothamnion,
Thallus with creeping rhizoids and upright oppositely or alternately pinnate fertile shoots. Fruit-mass with 1 gonimoblast 2. Ptilothamnion.
[Footnote] * The term “ramuli” has been used throughout this paper to denote short limited branchlets, frequently in whorls at the nodes (Ger. Kurztrieben).
Griffithsieæ.—Thallus naked or provided with very delicate verticillate ramuli. Cystocarps terminal on special fertile branches. The fruit-mass of 1 or 2 gonimolobes.
The sporangium bearing whorl of ramuli intercalary or apparently terminal. Some of the ramuli sterile, some fertile 3. Griffithsia.
The sporangium bearing whorl of ramuli near the end of the shoot. The inner ramuli short, branched, and bearing sporangia, and enclosed by one-celled sterile ramuli 4. Pandorea.
Monosporeæ.—Branches of a single row of naked cylindrical cells. Cystocarps terminal on the fertile shoots, with 1 gonimoblast.
Sporangia divided into more than 4 spores
Callithamnieæ.—Main axis of a single row of naked cells, the lower part clad with rhizoids. Cystocarps lateral, without involucre.
Sporangia divided into tetrads. Fruit-mass of several rounded gonimolobes 6. Callithamnion.
Spongoclonieæ.—Main shoot naked, covered with a spongy network of long-celled laterally-branched filaments. Cystocarps terminal on very short lateral branches, thus appearing sessile. Cystocarps of several rounded successively formed gonimolobes, sometimes enclosed in a small-celled patelliform involucre.
Thallus round, covered with a spongy network. The central axis branched alternately at the joint-cells, not coated with rhizoids. Cystocarps external on the network of the thallus, closed on the underside by the filaments, without patelliform involucre
Ptiloteæ.—Cell rows of the branches naked or with ramuli. Thallus either coated with rhizoids or with a normal closed cortex. Cystocarps generally enclosed by several involucral branchlets.
Branches coated with rhizoids or with a normal cortex. Apical cell diagonally segmented. Cystocarps terminal on short fertile pinnæ 8. Euptilota.
Crouanieæ.—Main axis either of a single row of cells with very richly branched ramuli, or with a central axis and cortex, consisting of richly branched filaments tightly packed together.
Thallus filamentous, main shoot consisting of a single row of cells. Cystocarps in the axil of a solitary ramulus
Thallus filamentous, main shoot consisting of a single row of cells. Cystocarps terminal 10. Antithamnion.
Spyridieæ.—The thallus possesses a central axis which is completely or partially clothed with a cortex consisting of larger cells within and smaller cells without.
Thallus rounded, branched on all sides, with large-celled central axis The cortex ring internally large-celled, externally small-celled, and broken only on the weaker shoots 11. Spyridia.
Thallus rounded or flattened, dichotomously branched, the dichotomous branches bent inwards like a pair of pincers. Central axis large-celled. Cortex ring continuous, or found only at the nodes 12. Ceramium.
Thallus completely corticated, with conspicuously large cells internally and small externally 13. Microcladia.
Thallus filamentous with creeping rhizoids and erect fertile branchlets. Branches consisting of single rows of cells 14. Rhodocorton.
Genus 1. Spermothamnion (Areschoug).
Thallus filamentous with creeping rhizoids attached by haptera, and erect more or less distichously oppositely or alternately branched fertile shoots. Sporangia placed on the lateral branches of the erect shoot, singly or in groups, divided into tetrads. Antheridia rounded, placed on the upper sides of the lateral branches. Cystocarps terminal in groups, tightly enclosed by the involucral branchlets, without pericarp. The fruit-mass consists of 2 paired united gonimoblasts, which are stout and small, with slightly convex loosely woven upper surface, from which the external cells spread out radially and subsequently produce large oval spores.
I have introduced the generic description because I have seen specimens apparently belonging to this genus, from the Sumner Estuary, Dunedin, and Dusky Sound, but the material has been insufficient for the proper definition of the species.
Genus 2. Ptilothamnion (Thuret).
Thallus filamentous, rhizoids provided with holdfasts and upright paripinnate (more seldom alternately branched) thallus. Sporangia generally terminal on the pinnules, divided into tetrads. The antheridia and procarps in exactly similar situations. Antheridia oval or elongated. Cystocarps terminal, enclosed in an involucre of a few involucral branchlets, appearing as very small oval tightly closed heads with a single very small stoutish gonimoblast; from this rounded surface the scanty external cells are only partially disengaged, and then subsequently ripen into spores (in basipetal sequence).
1. Ptilothamnion schmitzii (Heydrich, “Berichte der Deutschen Botanischen Gesellschaft,” vol. xi., 1893).
Thallus carmine-red, ½—1 mm. high, carpeting Zonaria sindairii (Hook. and Harv.), composed of monosiphonous filaments, which remain naked. The first filaments are creeping, 20–30 μ broad, fastened by means of short holdfasts to the substratum; secondary branches upright, simple, seldom branched, 16–20 μ broad. Cells half as long again to twice as long as broad. Procarps either sessile on one-celled secondary filaments, or upon a one or two-celled stalk on the first or second cell of the filament, overarched by 1 short bent covering ramulus, and consisting of 4 carpogonia. The cystocarps, which are attached similarly to the procarps, are small, rounded, and contain in a colourless pericarp 28 to 30 carpospores. They are overarched by a single large covering-branch. Antheridia are composed of oval bodies at the point of a secondary filament, and have an articulated filamentous axis. Sporangia solitary or in pairs on one or two-celled
lateral branches. Tetraspores in tetrads. All the reproductive organs come off close together from the same patch of thallus.
Hab. In the Bay of Islands (in June).
I have seen no specimens of this. (R. M. L.)
2. Ptilothamnion pectinatum, R. M. L. (? = Callithamnion pectinatum, Mont., Prodr. Phyc., p. 9). Plate XXIV., figs. 1 and 2.
Thallus minute, 3–6 mm. in length, and linear to linear-lanceolate in outline, oppositely distichously pinnate and sparingly bipinnated. Cells of rachis 30–50 μ in length and 15–25 μ in breadth. Pinnæ at the base of the rachis generally simple, from ½–1 mm. in length, a pair springing from each cell. Towards the middle of the rachis they are sometimes compound. They occasionally branch dichotomously, and are provided with a pair of pinnules to each cell. The axils of pinnæ and pinnules are about 45°–60° measurement. The pinnæ consist of about 20 cells, about 30–40 μ in length and 10 μ in breadth. The pinnules are from ¼–½ mm. in length, with similar cells to those of the pinnæ. The tetraspores are in tetrads, terminal, and generally solitary at the ends of the pinnules; however, a second tetrasporangium is occasionally formed subsequently to the discharge of the first. The cystocarps are also terminal on the pinnules, the procarps being very similar to those described by Heydrich for Ptilothamnion schmitzii, and of very simple character. In some cases a second cystocarp is apparently formed close to the first, but I am not quite certain of this, as my specimens are somewhat entangled and in bad condition. The cystocarps apparently are readily detached, as I have not yet found a mature one in the position of the procarp, but they are always entangled among the pinnæ.
Distribution.—Auckland Islands (Montagne); Half - moon Bay, Stewart Island (R. M. L., J. C. S.): on a species of Cladophora (? Cladophora colensoi).
This is the first time this pretty little plant has been recorded since the voyage of the “Astrolabe” and “Zélée” in 1841. The identification is in the first place due to Agardh, to whom I sent specimens. He apparently regarded it as undoubtedly the same as Montagne's specimens, of which perhaps he may have had a type. The description of Montagne's plant, which may be given here for the sake of comparison, agrees well enough with mine, except as to the tetraspores: “C. pectinatum (Mont., Prodr. Phyc., p. 9). Microscopicum, filo primario repente pinnato, pinnis pinnulisque oppositis patentibus, articulis cylindricis diametro duplo longioribus aut æqualibus; tetrachocarpiis axillaribus.”
The “axile tetraspores” (tetrachocarpiis axillaribus) does not agree well with the terminal tetraspores in my plant. Indeed, the New Zealand species seems to come close to the British Ptilothamnion pluma (see also under Antithamnion ptilota). I have, however, retained Montagne's specific name. This course is scarcely likely to cause confusion, and so it seemed unnecessary to describe the plant as new. I have therefore also accepted provisionally Agardh's identification.
Genus 3. Griffithsia (C. Agardh).
Thallus erect, pinnately or dichotomously branched. The branches are composed of single rows of large cylindrical cells, which are often expanded in the centre and constricted at the nodes, thus becoming cask-shaped. They are naked or provided with delicate ramuli arranged in whorls, which bear axile sporangia. These, in consequence of the obliteration of the point of the shoot, sometimes appear terminal, and the ramuli thus form an involucre consisting of fertile or partly of fertile and partly of sterile branchlets. The sporangia are divided into tetrads. The antheridia are thickly packed together or are arranged analogously to the sporangia tightly packed together or in somewhat loose bundles. Procarps terminal on special sometimes abbreviated or rudimentary branchlets, and developed out of 2 or 3 of the terminal joint cells of the shoot. The cystocarps terminal on shortened frequently quite abbreviated shoots, with an involucre of ramuli. The fruit-mass consists of 1 seldom of 2 gonimoblasts, collected into a single mass, or more generally divided into several successively developed gonimolobes. Almost all of the cells of the gonimolobes produce spores.
A genus of 20–30 species, found chiefly in the warmer seas. Typical species are G. corallina (C. Agardh), G. setacea (G. Agardh).
1. Griffithsia sonderiana, J. Agardh. Chief synonymy: G. sonderiana, J. Ag., Epicr. Florid., p. 62. G. setacea, Harv., Handbook of the N.Z. Flora, p. 709. Callithamnion griffithsioides, Harv., Phyc. Austr., pl. 160. G. (?), comosa, Grun. “Novara,” p. 62, pl. x. Plate XXV., fig. 1.
The plant consists of masses of closely packed rather flaccid more or less irregularly dichotomous filaments. Dichotomy takes place about once every centimeter, or at every fourth or fifth cell. Branches fasciculated, fastigiate, 10–15 cm. long, and in dried specimens ⅕ mm. in diameter. In fertile specimens below the apices appear a number of short lateral compound ramuli, more or less irregularly disposed, sometimes secund, at
other times dichotomous and fastigiate, in the axils and at the nodes of which the sporangia are formed. There is no involucre, but the sporangia are generally supported on a pedicel cell, and are at first solitary, though at length more are evolved at the side of the first. The lower cells of the branches are as much as twelve times as long as broad, the upper are about six times as long as broad. As in other plants of the genus, the cells when put into fresh water burst with a crackling sound and discharge their red colouring-matter. Cystocarps and antheridia unknown.
Distribution.—Australia, Tasmania; New Zealand—Riverton, The Nuggets, Port Chalmers, Moeraki, Oamaru, Lyttelton (R. M. L.); Green Island Beach, St. Clair, Warrington (J. C. S.); Chatham Islands (Canterbury Museum).
2. Griffithsia antarctica, Harv., Fl. Ant., vol. ii., p. 488; J. Ag., Epicr. Florid., p. 68. Plate XXV., fig. 2.
Fronds tufted, flaccid, rather sparingly branched, dichotomous, sometimes more or less irregularly pinnate towards the upper part; shorter, stouter, and much less tufted than G. sonderiana; from 8–12 cm. long, and about ½ mm. in diameter. Cells of the main axis 1200–1500 μ long and 400–500 μ, broad. The fertile branches are somewhat inflated, and at length give off a short lateral branch, at the penultimate or antepenultimate cell of which a cuplike involucre is formed enclosing the tetra-spores. The cells beyond this gradually become absorbed or disappear. The involucre consists of about 15 linear-oblong ramuli, enclosed at first in a corolla-like cup, but afterwards opening for the escape of the fasciculated tetraspores. In mature specimens the involucral cup frequently appears terminal on a single obconic cell, but at other times it is supported by a pedicel consisting of several cells. I have not been able to determine whether this difference is specific or only varietal. Antheridia and cystocarps unknown.
Distribution.—Tasmania; New Zealand—Akatore, Timaru, Taylor's Mistake (R. M. L.); Green Island, St. Clair, Warrington (J. C. S.); Foveaux Strait, Stewart Island (Lyall); East Coast (Colenso).
This plant may be readily distinguished from the preceding species by the very different arrangement of the tetraspores. Its generic position is uncertain. It may possibly belong to Pandorea or Bornetia, but until the cystocarps are discovered it should perhaps be left here. In Pandorea the ramuli surrounding the tetraspores cohere as in a gamopetalous corolla. In G. antarctica, according to Agardh, they are free, and this constitutes one of his chief diagnostic distinctions between the two
genera. This distinction, however, appears to me to exist only when the two species are compared at different stages of growth.
Agardh thinks (Epicr. Florid., p. 69) that possibly two species differing only in their vegetative characters are included in this species—one closely resembling Bornetia binderiana; and this may turn out to be the case. The plant is not so common as G. sonderiana, and hitherto I have only obtained comparatively few specimens of it, and so am not in a position to say whether it really contains more than one species or not.
Genus 4. Pandorea (J. Agardh).
Thallus irregularly dichotomously branched, of a single row of large cells, articulate, and in all respects similar to that of Griffithsia. Sporangia developed in special whorls of ramuli near the end of the shoot.* The branchlets of these fertile whorls are differentiated into short compound sporangia bearing ramuli, and into sterile one-celled covering ramuli, which are tightly locked together into a cup, enclosing the others, and reminding one of the corolla of one of the higher plants. These one-celled petaloid ramuli are from 30 to 40 in number. Antheridia and cystocarps unknown.
1. Pandorea traversii, J. Agardh. Plate XXVI.
The genus is monotypic. The number of parts in the cup surrounding the fertile ramuli, and the contiguity of the petaloid cells, serve at once to distinguish this species from the preceding, which it resembles much in other ways. It is, however, stouter, shorter, and much less branched than Griffithsia antarctica. Frond inclining to be erect, subfasciculate, axils of branches rather acute. The cells about two or three times as long as broad, and from 1/2–2/3 mm. in diameter. The involucral cup is stuffed with very slender threads, bearing large tetraspores in tetrads. Antheridia and cystocarps unknown. The plant was first described by Agardh from specimens collected by Travers at the Chatham Islands.
Distribution.—Stewart Island, Taylor's Mistake, Lyall Bay (Wellington), (R. M. L.); Chatham Islands (Travers).
Genus 5. Pleonosporium (Naegeli).
Thallus upright, filamentous, repeatedly alternately pinnately branched with the pinnules decreasing in length towards the apex, more rarely dichotomously branched. Branches consisting of single rows of cells. Lower portion of the main shoot sometimes coated with rootlets. The sporangia are placed on
[Footnote] * Vide J. Ag., Florid. Morph., tab. i., figs. 1–8.
the upper pinnules of the thallus, and on the upper side of the pinnule: they are divided into numerous radially arranged spores. Procarps small, terminal, on the upper pinnules of the thallus, each with a single fertile cell. Cystocarps terminal, protected by a single lateral branchlet. Fruit-mass built up of 1 gonimoblast, divided into several rounded successively formed gonimolobes.
1. Pleonosporium brounianum, Harv.-Gibs. (= Callithamnion brounianum, Harv., Trans. Royal Irish Acad., xxii., p. 561). Plate XXVII., fig. 2.
Thallus dark-brown, 10–15 cm. high, irregularly alternately (more rarely oppositely) pinnately branched in all directions, with rhizoids descending along the whole length of the stem and branches from the basal cells of the pinnæ. The pinnules are long and filamentous, and the lower ones clothe the stem and branches with a matted mass of filaments, completely concealing the general branch system. The main rachis has comparatively few pinnæ, but the pinnæ are themselves pinnately decompound. In typical specimens the last series of pinnules at the tips of the branches are stout, more or less distichously corymbose and arcuate. In many specimens the apices are completely covered by filamentous pinnules growing up from below, which are prolonged beyond the growing-point in fastigiate masses. The axils of the terminal pinnules are acute, and the cells of which they are composed approximately square. As the frond is descended the axils become more patent, and finally the pinnules branch at an angle of from 60°–80°. The cells of the main stem are about 300–400 μ long and 100–150 μ broad. The cells of the pinnæ are of a similar type but rather smaller, of the pinnules very varied in relative dimensions. Those of the terminal pinnules are 40–50 μ long and 25–40 μ broad; but in the filaments cells may be obtained 150–200 μ long and only 25–40 μ broad. The sporangia are placed on the inner sides of the pinnules, rather sparsely at first. They are pear-shaped and undivided, but afterwards contain 8, 16, or 32 radially arranged spores, always more than 4 when mature. The cystocarps (according to Harvey-Gibson) are binate, terminal, and involucrate. Antheridia unknown.
Distribution.—Western Australia, Victoria (Bracebridge Wilson); Brighton, Dunedin (R. M. L.); St. Clair (J. C. S.).
This plant was first described from New Zealand by Professor Harvey-Gibson from specimens collected by Professor T. J. Parker (no locality given). As in the following species, the vegetative structure is that of Spongoclonium, but the sporangia fix it in the genus Pleonosporium. This plant may possibly
not be specifically distinct from the following one, as both species seem to vary considerably, but they are distinct enough in their extreme forms.
Both plants require much fuller investigation and description than they have yet received.
2. Pleonosporium hirtum, R. M. L. (= Callithamnion hirtum (partim), Hook. and Harv., Fl. Antarctica, 192, t. 78, f. 2). Plate XXVII., fig. 1.
Thallus a dull purple-lake, tufted, 8 to 10 cm. high, irregularly alternately pinnately branched in all directions. Main stem often short or altogether wanting, the base sparingly coated with minute cells. Its articulations from 400–500 μ in length and 150–250 μ in breadth. It and the main branches are coated by decurrent rhizoids from the terminal cells of the pinnæ. The pinnæ are alternate and bi- or tri-pinnately branched, with cells intermediate in character between those of the rachis and terminal pinnules. The pinnules, excepting those near the apices, are long and filamentous, with cells of varying size and shape, and sometimes six to eight times as long as broad. These filaments are woven together into an inextricable network of small mesh covering about two-thirds of the entire surface of the plants, the ends of the pinnæ in older specimens alone being free from it. The plant is thus not so completely covered by the network as P. brounianum. The apices of the pinnules are free for the length of from 1–2 mm., and beset the plant on all sides, thus giving the plant that furry or shaggy appearance to which it owes its name. The apical pinnules often di- and sometimes tri-chotomously divided at their tips, and several often coalesce longitudinally to form a single branch. This perhaps gives rise to the veined appearance referred to by Harvey. The cells of these pinnules are from 60–80 μ long and 30–40 μ broad. They form penicillate masses completely surrounding and extending beyond the main growing-point. Sporangia of the Pleonosporium type, in series on the pinnules. Antheridia and cystocarps unknown.
Distribution.—St. Clair (J. C. S. !); Lyttelton (R. M. L.).
I am probably not wrong in identifying this plant with Harvey's Callithamnion hirtum, with which it corresponds exactly in general appearance and vegetative structure. Harvey, however, in his drawings shows tetraspores divided into tetrads; but this, I think, is to be explained by the fact that his species probably included not only Pleonosporium hirtum, P. brounianum, but perhaps also the Spongoclonium to which I have given the name S. pastorale. In my own collection there is a young plant bearing sporangia, collected at the same time and place as
older and infertile specimens. It is very different in appearance from them, for the rhizoids are undeveloped. After the sporangia are discharged the colourless cases remain behind, and apparently only gradually decay.
Genus 6. Callithamnion (Lyngbye).
Thallus upright, much dichotomised or laterally branched on all sides (or distichous in the upper part), with monopodial or sympodial arrangement. The branches consist of single rows of naked cells with more than one nucleus. The main branch frequently coated with rhizoids below. Sporangia in tetrads (sometimes cruciate according to some) on the upper branches of the thallus, attached laterally on the upper side (one or more on a single cell). Antheridia generally very small, consisting of thickly packed bundles of very various but analogous arrangement to that of the sporangia. The cystocarps attached laterally to the upper part of the thallus (more rarely apparently terminal), without an involucre, consisting of a pair of gonimoblasts (more seldom one), which put forth on a smaller central cell several successively formed rounded gonimolobes.
1. Callithamnion byssoides, Arnott (Harv., Fl. N.Z., ii., 260; J. Ag., Epicr. Florid., p. 29).
Thallus somewhat erect, alternately pinnately decompound, corticated at the base only, very flaccid, with the branches and branchlets coming out from all sides, the upper branchlets dichotomous and incurved, sublanceolate in outline, equal in length or shorter than the one on the inside. Tetraspores sparse on the inner side of the axils, the young ones obovate-clavate, ripe ones subrotund in tetrads. I have seen no description of cystocarps or antheridia, but the former at least are known.
Distribution.—The warmer Atlantic shores of Europe and America; Tasmania.
Var. caulescens (J. Ag., Epicr. Florid., p. 39), with a firmer stem which is corticated for a considerable distance upwards with decurrent threads enclosed in a membrane. Foveaux Strait and Otago Harbour (Lyall); Maketu (Chapman); Otago Harbour (J. C. S.).
The specimens I have seen, collected at the Maori kaik (Dunedin Harbour) by Mr. J. C. Smith, belong to Agardh's var. caulescens, which is probably a distinct species. The main axis and all the branches are corticated, the plumules alone being free. The articulations of the main stem and branches are thus completely hidden. The plant is 15–20 cm. high, irregularly alternately branched. The terminal pinnules are dichotomous, incurved, and subcorymbose at the tips. The lower portions of
the stem and main branches are not provided with pinnules, the tips of stem and branches are thus rather plumose. The cells of the pinnules are from 150–180 μ long and about 30–40 μ broad. The cells of the cortex vary much in their dimension, and are from two to four times as long as broad. I have seen no reproductive organs on this plant.
2. Callithamnion colensoi, Harv., Fl. N.Z., ii., 259. Plate XXVIII., figs, 1a, 1b.
Frond dark-purple, robust, dendroid, 2–3 in. high. Main stem as thick as a sparrow's quill below, internodes coated with small cells, laterally branched; branches densely clothed all round with minute compound squarrose imbricated ramuli; ultimately divaricate, subulate-acute, alternate; articulations coated with small cells, one and a half times longer than broad, ultimate pellucid.
Distribution.—East Coast and Hawke's Bay (Colenso).
I have a fragment of a plant on a microscope-slide which probably belongs to this species. It was collected at the Nuggets. Unfortunately, I do not seem to have any mounted specimens of it. The rachis and pinnæ are alternately branched, lanceolate in outline, and each of the younger pinnæ is developed inside a membrane, from which it finally escapes. This is evidently a highly characteristic feature of the plant. The ramuli are compound, and from 80–100 μ in length. The cells composing them are minute and approximately square, with a length of 15–25 μ. The tetraspores are arranged along the pinnules in some cases in two, three, or four longitudinal rows, but in other cases no orderly arrangement can be made out. They are developed in the axils of the ramuli, which clothe the whole plant in the manner described above, i.e., “with minute compound squarrose imbricate branchlets.” The ramuli bear divaricating processes, which are sometimes secund, and at other times irregularly alternate and dichotomous. The plant is completely corticated with small cells. Articulations of the ultimate pinnules are about twice as long as broad.
3. Callithamnion consanguineum, Harv., Fl. N.Z., ii., 295.
Fronds densely tufted, flaccid, rose-purple, 2–3 in. high, capillary, excessively branched; branches spreading, the smaller distichous above, alternately decompoundly pinnate and alternately plumulate; plumules short, flabellate, naked below, pinnate above, terminal; pinnæ close-set; articulations opaque, with cortical cells two to three times as long as broad; upper pellucid. Tetraspores lateral, subsolitary, triangularly divided.
Distribution.—Port Nicholson (Lyall); the Esplanade (Wellington), Petone (R. M. L.).
I have specimens, which agree exactly with the above description (Harvey's), from Wellington Harbour, but I have not seen tetraspores, cystocarps, or antheridia. The plant has not been recorded hitherto since collected by Lyall.
Genus 7. Spongoclonium (Sender).
Thallus upright, rounded, provided with unequally long similarly branched pinnæ on all sides. These produce filamentous pinnules, which form a spongy network covering the plant. The lower cells of the pinnæ send out rhizoids, which, becoming decurrent, clothe the main stem and branches with a gradually thickening covering. Sporangia shortly stalked, and divided into tetrads attached singly or in series to the free ends of the pinnules. Antheridia in closely packed tufts, similarly arranged to the sporangia. Cystocarps scattered over the surface of the thallus in large numbers, terminal on branches so short that they appear seated on the network of the thallus. The thallus filaments are more richly developed under the cystocarps, so as to enclose them on the underside, but there is no cuplike involucre. The spore-mass consists of 1 gonimoblast, which divides into numerous successively formed rounded very small gonimolobes. Gonimolobes tightly closed with all cells giving rise to carpospores.
(The cystocarps are unknown or insufficiently described in the New Zealand species, but there can be but little doubt that they are rightly inserted here.)
1. Spongoclonium pastorale, sp. nov. (R. M. L.). Plate XXVIII., fig. 2.
Thallus dark-brown, sometimes blackish, 3–6 cm. high, irregularly alternately pinnate. Main branches rather few, flexuose. Rachis and pinnæ coated with decurrent rhizoids. Pinnules flexuose, woven into an inextricable network. Terminal pinnules patent, often divaricating, subdistichous (though 3 or 4 occasionally arise from one cell), sparingly branched, but sometimes bearing pectinate ramuli on the upper side. The ends of the pinnules often crooked like a shepherd's staff, or sharply bent. Cells of pinnules about 80 μ long and 50 μ broad, of the axis about 200 μ long and 60–80 μ broad, those of the pinnæ similar but rather smaller. Tetraspores numerous in series on the pinnules, divided into tetrads. Cystocarps and antheridia unknown.
Distribution.—Wycliffe Bay (Otago Peninsula), (R. M. L., J. C. S. !).
2. Spongoclonium brachygonum, R. M. L. (? = Callithamnion brachygonum, Harv., Fl. N.Z., ii., 259). Plate XXIX., fig. 1.
Thallus 6–8 cm. high, dull-red, densely tufted, without apparent main stem or branches, irregularly alternately pinnately decompound. The pinnules are long interlacing filaments which cover the whole plant with a somewhat open network, but become shorter near the apex in acropetal succession. The terminal pinnules are more or less distichous, but occasionally secund. The plant bears some external resemblance to Pleonosporium brounianum and P. hirtum, but it is much more slender and delicate than either, and the network of pinnules, though more open than in either of the other two, covers it more completely. The pinnules at the apices are much more open and loose than in P. hirtum, and much longer and not flabellately expanded as those in P. brounianum. Tetraspores solitary, lateral, rather sparse, divided into tetrads. (For cystocarps see below.)
Distribution.—Purau (Lyttelton), Wellington (R. M. L.); Warrington (Berggren).
I have seen a distinct variety or possibly a new species collected by Mr. Cresly Smith at St. Clair, but in the absence of more material I hesitate to describe it. It may possibly be the true S. brachygonum, for it possesses the rod-like branchlets referred to by Harvey, which this plant does not. However, my plant was originally determined by Agardh, and I translate his remarks on the species in reference to some specimens obtained by Berggren at Warrington*: “I have seen no plant of Harvey's. With great hesitation I refer to this species a little plant about an inch in length gathered at Warrington by Berggren. It is certainly a Dasythamnion with the stem clad with decurrent filaments. Harvey has not a word about this character. The branches are pinnately elongated, subcorymbose at the apex, with rather dense incurved ramuli. The pinnæ are decussate below, with the pinnules lateral or extrorse, all patent or somewhat erect, and rather obtuse curved over the apex. Cells of the pinnæ twice as long as broad, of the pinnules half as long again or equal. Twin cystocarps of the usual rounded form below the apex of a pinna.”
It will be seen that Agardh's description differs in various points from mine, but in his determination of my specimens he seems to me to have confused under the title C. brachygonum plants of P. hirtum and C. brachygonum. Hence I scarcely feel justified in relying upon his identification of S. brachygonum with Harvey's C. brachygonum. I therefore transcribe from the
[Footnote] * De. Alg., N.Z., Mar., p. 13.
Flor. N.Z., ii., p. 259, Harvey's description, as some future investigator may meet with a plant which agrees with it more closely than this does. Should this prove to be the case, I would suggest that this be described as a new species under the name S. agardhii. I have deposited specimens of what seem to me to be typical forms of this and of the species of Pleonosporium in the Canterbury Museum, and as they are quite distinct any subsequent worker in New Zealand will readily be able to determine whether any similar form he may find agrees with them or not.
Callithamnion brachygonum,* Harv., Fl. Nov. Zel., ii., p. 259.
“1 or 2 in. high, densely tufted, flaccid, bright carmine-red. Stem subsimple, set on all sides with lateral similar branches, which bear a second or third series of similar rod-like branchlets, the last series of which are clothed with subdistichous plumules. Plumules very narrow, erect, patent, the lower most simply pinnate, the upper gradually longer and more compound, those near the middle of the branches very long and bipinnate. All the articulations are short, those of the stem and branches veinless with narrow endochrome and thick walls. Tetraspores line the inner faces of the ramuli.”
Genus 8. Euptilota (Kuetzing).
Thallus erect, very richly distichously branched, flattened on both edges, coated with rhizoids in the lower part or nearly to the top, or enclosed in a more or less thick normal cortex throughout its whole length. Shoots of two kinds, (a) of limited (b) of unlimited growth. Those of unlimited growth are alternately pinnate with entirely or alternately pinnatifid or alternately pinnately compound or decompound limited branches, of which some develop into unlimited branches. Apical cell of the unlimited branch diagonally segmented. Sporangia in the upper part of the thallus on short articulated naked stalks, which shoot out singly or in groups, or are united into branched bundles, upon the edges (especially the upper edges) of the limited pinnæ. Antheridia (as far as is known) small stout bundles of branches growing out of the edge of the limited pinnæ. Procarps on short pinnæ, or on the teeth of the pinnæ of somewhat enlarged limited shoots near the point. Cystocarps terminal on the short fertile pinnæ, sometimes apparently laterally placed, enclosed by more or less numerous subsequently developed involucral ramuli.
The typical species is Euptilota formossissima of New Zealand.
[Footnote] * I have adopted the description given in the Flora in preference to the translated description of the Handbook, as the former appears to me to be the more intelligible of the two.
1. Euptilota formossissima, Kuetz. (= Ptilota formossissima, Mont., Prodr. Phyc. ant. p. 8.; Harv., N.Z., ii., 257; Fl. Antarct., 190, t. 77; J. Ag., Epicr. Florid., p. 79).
Thallus 20–30 cm. long, pinnately decompound, with the pinnæ alternate, the pinnules pinnatifid, and the whole plant completely corticated to the apex; the ultimate pinnules are serrate, with the serrations gradually growing narrower from a somewhat broad base to an acute or mucronate apex. Tetraspores triangularly divided, numerous on the teeth, on a scarcely conspicuous articulated pedicel amongst similar not fertile filaments. Cystocarps enclosed in corticated pinnatifid ramuli. Antheridia unknown (?).
Distribution.—Common on the New Zealand coasts; Chatham Islands.
This is a well-known and very handsome species. The pinnæ are as described for the genus, of two kinds, limited and unlimited in growth. Those of limited growth are more than ten times more numerous than those of unlimited growth, which seem to be placed irregularly, but generally give the plant the appearance of being more or less flabellately decompound. The pinnæ of limited growth are from 4–8 mm. in length.
2. Euptilota pellucida, R. M. L. (= Ptilota pellucida, Harv., Fl. N.Z., ii., 257; J. Ag., Epicr. Florid., p. 75). Plate XXIX., fig. 2.
Thallus 8–12 cm. in length, roughly ovate or elliptical in outline, distichously oppositely pinnately decompound, with pinnæ of limited and unlimited growth, but branching more regular than in E. formossissima. The main stem and bases of chief pinnæ only corticated, and the cortication much less dense than in E. formossissima. The articulations of pinnæ and pinnules naked. The last series of pinnules pectinate, or pinnate and the opposite ones often unlike, one being more or less undivided and the other much divided. The pectinations are either on the upper or lower side of the pinnule, and are filamentous and subulate. The apical cells of the pinnæ of unlimited growth are diagonally segmented. The tetraspores are lateral, solitary, sparse, with short pedicel, or often apparently sessile, and cruciately divided.
Distribution.—Otago, Stewart Island (Lyall); St. Clair (J. C. S.); Lyall Bay (R. M. L.).
A much less common plant than the preceding, and of much more delicate structure altogether. Its position seems to me to be uncertain. Agardh places it in his division of the genus: “Pinnis oppositis, utraque pagina conformi, magnitudine aequali aut una majore,” and in his description of the species says the
pinnæ are opposite and similar (“pinnis in rachide filiformi oppositis conformibus”); but Agardh is here in error—the pinnæ are almost invariably unlike. Further, Agardh had not seen the tetraspores: their method of division, and the fact that they are often sessile, may place this plant outside the group Ptiloteœ altogether. Perhaps, however, until the cystocarps are known, and its position thus made more definite, it may be provisionally retained here. The segmentation of the apical cell of the unlimited pinnæ places it in the genus Euptilota rather than in the genus Ptilota. Agardh states that it is parasitic on Hymenocladia. I have found it more often epiphytic on E. formossissima, but also on other plants.
Genus 9. Ballia (Harvey).
Thallus upright, filamentous, richly generally distichously branched. Main axis of a single row of cells, with opposite (seldom whorled) simply or compoundly pinnate similar or alternately unlike pinnules, covered below with a thickly woven felt consisting of branched filaments which grow out of the bases of the pinnules, also frequently coated in the lower parts with rhizoids which tightly enclose the main axis. Sporangia cruciate or in tetrads, terminal on the pinnules of special generally irregularly branched basal pinnules. Antheridia (so far as is known) in small stout loose bundles on the points of the ultimate pinnules. Carpogonium bearing branch, four-celled, slightly bent, solitary, fastened to the basal cell of a few elongated pinnules. Fertile pinnules distributed over the plant, mostly on the shorter thallus branches. The auxiliary cell is developed from the fertilised cell of the carpogonium branch. Cystocarps generally developed in rows on the axil of a somewhat elongated very shortly stalked pinnule, enclosed as by an involucre by the subsequently developed richly branched basal pinnules of the fertile shoot. There is a single gonimoblast which develops into several or numerous rounded gonimolobes.
1. Ballia callitricha, J. Ag., Syst., p. 166 (= Ballia hombromana, Mont., Voy. au Pole sud, t. 12, f. 1. Ballia brunonis, Harv., Fl. Antarct., 182. Ballia callitricha, J. Ag., Epicr. Florid., p. 58).
Root a spongy disc. Thallus densely tufted, 4–20 cm. in length, with stout rigid stupose stipes, distichously pinnately decompound, with the pinnæ and pinnules opposite, similar, and lanceolate in outline, and very closely set, with the last series simple and more or less acute.
The following varieties, dependent on age, are distinguished by Agardh: (a) normalis, with the pinnæ very densely decompoundedly pinnate, pinnules plumose; (b) pennata, with the
pinnæ very thickly pinnate, the pinnules simple; (c) simplicipilum, the branches rather laxly pinnate, the pinnæ filiform, elongated.
Distribution.—Common on the east coast of the South Island, and probably elsewhere in New Zealand. Auckland and Campbell Islands (Harv.); Macquarie Islands (A. Hamilton); Australia, Fuegia, Falklands, Kerguelen, &c.
The minute structure of the plant has been described by W. Archer in a paper read before the Linnæan Society on the 15th June, 1876. In every joint-cell of the plant there occurs in the dissepiment a minute “pit,” which is afterwards closed by a “stopper.” In a “sinus” placed laterally on the joint-cells is formed a special cell, called by Archer a “ramification cell,” which is either pentagonal or hexagonal. This becomes inflated towards the upper end, which is finally cut off by an oblique septum, and this cell becomes the first joint of a simple branch or subsidiary rachis. “The lower portions of the main stems are covered all round by a single layer of thick-walled elongated cells, mutually closely apposed, of variously irregularly curved and crooked figure…. This cortical stratum of cells somewhat resembles a kind of pleurenchymatous or prosenchymatous tissue.” The development of this tissue is also traced back to ramification cells. The cortical cells themselves are also repeatedly dichotomous, and give rise to a considerable portion of the accessory filamentous investment of the plant. Many of the filaments, however, are developed from subsidiary ramification cells, or from cells adjacent to them. For a full understanding, however, of the complicated structure of the plant reference must be made to Professor Archer's paper. I have given this very short account of its development, however, as it seemed to me that the generic description of Schmitz given above was perhaps somewhat misleading.
2. Ballia scoparia, Hook. and Harv., Lond. Journal, iv., p. 173 (= Callithamnion scoparium, Fl. Nov. Zel. ii., p. 259. Ballia scoparia, J. Ag., Epicr., p. 59; Harv., Phyc. Austr., t. 168. Rhodocorton parkeri, Harvey-Gibson, Journ. of Bot., 1893, p. 161). Plate XXX., fig. 1.
Thallus 10–20 cm. high; frond spreadingly branched, with branches coming off in all directions and covered on all sides with fasciculate decompound appressed ramuli. The stem and root similar to that of B. callitricha, stupose. The terminal pinnules near the apices of the fascicled ramuli, subsecund, acuminate, and furnished with 2 or 3 lateral spines. The sporangia are terminal on the pinnules, or lateral and subsecund, cruciately divided. Joint-cells about half as long again as broad.
Distribution.—Common along the coast of the South Island, and probably elsewhere; Australia, South America.
I have examined one of Professor Harvey-Gibson's type specimens of Rhodocorton parkeri, and I have no hesitation in saying that it is a very young specimen of this plant. The spines, which, according to Professor Gibson, in his plant “form the most characteristic and diagnostic feature of the species,” are equally characteristic of B. scoparia. The segmentation of the cells is that of B. scoparia, and not of a Rhodocorton. The arrangement and division of the tetraspores is the same in each. Specimens of each are indistinguishable in their appearance under the microscope; the relative dimensions of the cells are the same, and rhizoids are developed similarly on both. Rhodocorton parkeri was found at the base of a thallus of Lychaete darwinii.* Lychaete darwinii and Ballia scoparia are found so frequently epiphytic one upon the other that their constant companionship seems almost to suggest commensalism. Apparently, then, there is every reason for regarding R. parkeri as merely a synonym for B. scoparia.
Genus 10. Antithamnion.
Thallus filamentous, generally dichotomously branched with sympodial growth. The main axis consists of single rows of cells with opposite or whorled generally richly branched ramuli. On the branches of the ramuli are often formed peculiar gland-cells. The sporangia are terminal on the branches of the ramuli, and divide cruciately. The antheridia are small bundles of branches terminal on the ultimate branch of the ramulus. Fertile ramuli are distributed over the shoot or collected in bundles close to its end. The development of the terminal cells is then arrested. The cystocarps thus become nearly terminal or apparently terminal. They are enclosed as with an involucre by the uppermost sometimes subsequently developed ramuli. In some species the sporangia-bearing plants develop paraspores in few or many-celled irregular masses at the point of the shoot.
1. Antithamnion applicitum, R. M. L. (= Callithamnion applicitum, Harv., Fl. N.Z., ii., 258). Plate XXX., fig. 2.
Thallus minute, investing the surfaces of other algae but not completely attached to them. Fronds 2–3 mm. in height, partially erect, nearly regularly oppositely pinnately distichously branched. A pair of pinnæ spring from below the apex of each cell and from opposite sides of it: these are generally compound, sometimes decompound. The pinnules are arranged similarly to the pinnæ, and both pinnæ and pinnules consist of
[Footnote] * Laing, Trans. N.Z. Inst., vol. xxvii., p. 300.
from 6–10 or occasionally more cells. Sometimes one row of pinnules is wanting or partially wanting: this is particularly the case at the apices of the thallus. Cells of rachis one and a half times to twice as long as broad, and from 100–150 μ in length. The pinnæ are about ½–⅔ mm. in length, though occasionally they are several times that length. The cells of the pinnæ are three or four times as long as broad, and rounded at the apex. The cells of the pinnules are about one and a half times as long as broad, and the pinnules themselves about ¼–⅓ mm. in length. The apical cells extend slightly beyond the pinnules in my specimens. In southern specimens these cells are acute, but in some from Wellington they are rather obtuse. Axils acute, and pinnæ sometimes curved. As in the allied species, the basal cell of each pinna is generally small and without pinnules. Tetraspores cruciate, probably solitary in the axils of the pinnules. Antheridia unknown. Cystocarp unknown.
Distribution.—Riverton, St. Clair (J. C. S.); Green Island Beach, Western Heads (Wellington), (R. M. L.).
I have seen no type specimens of this plant, and Harvey's original description is very imperfect, so that identification with absolute certainty is impossible; but this can scarcely be anything else than Harvey's C. applicitum, although my specimens are not completely attached to the other algæ on which they are epiphytic.
2. Antithamnion adnatum, R. M. L. (= Callithamnion adnatum, J. Ag., de Alg. N.Z., Mar., p. 12). Plate XXXI., fig. 1.
Thallus minute, at first creeping but afterwards nearly erect, 2–4 mm. in length, oppositely bi- and occasionally tri-pinnate. Each cell of the frond provided with 3 or 4 pinnæ (more rarely 2) arranged in rows. The plant is thus largely tri- or tetra-stichous. Cells of the rachis about 150–180 μ in length and 50–60 μ in breadth. The pinnæ are generally simple (about ¼ mm. in length), and consist of 12 to 15 or occasionally more cells, which are in length about 80–100 μ, and in breadth about 40–50 μ. A group of pinnæ come off from below the apex, and curving over it completely enclose it. The pinnæ are more or less arcuate, and the axils acute, so that their tips are generally in contact with the main rachis. Pinnules short, with cells about one and a half times as long as broad, or approximately square. Organs of reproduction unknown.
Distribution.—Bay of Islands (Berggren); Lyall Bay, Pukerua (R. M. L.); Riverton (J. C. S.).
In the absence of cystocarps and tetraspores the exact position of this plant is doubtful, but its vegetative structure is that of Antithamnion.
3. Antithamnion ptilota, Harv.-Gibs. (= Callithamnion ptilota, Hook. and Harv., London Journal, iv., p. 272).
Frond somewhat rigid, setaceous, with rather erect very densely branched pinnate filaments, the pinnæ nearly distichous, veined, with opposite pinnules. Pinnules simple, patent, subulate. Tetraspores sparingly on the pinnules. Cystocarps and antheridia unknown.
Distribution.—Crozets (Harvey): New Zealand (T. J. Parker).
This plant is recorded from New Zealand by Professor Harvey-Gibson in a paper “On some Marine Algæ from New Zealand” (“Journal of Botany,” 1893). I have also a plant from Half-moon Bay, Stewart Island, which Major Reinbold determined as a young specimen of this species, but it is the same as the plant determined for me by Agardh as C. pectinatum (vide supra, Ptilothamnion pectinatum), and it seems to me that it agrees with the description of C. pectinatum better than with that of A. ptilota. Further, it has tetraspores in tetrads, and according to Agardh they are cruciate in A. ptilota, but in tetrads in A. pectinatum. Harvey-Gibson's plant bore tetraspores, but he does not say of what sort, and I have not seen the original description of Harvey's of A. ptilota. The tetraspores in A. ptilota, according to the figure in the “Flora Antarctica” (tab. 189, fig. 1), are lateral, not terminal. Considering these differences, I do not think the plant determined for me by Major Reinbold as A. ptilota can be assigned to that species.
4. Antithamnion mucronatum, R. M. L. (= Callithamnion mucronatum, J. Ag., Ep., vol. ii., p. 29; Harv., Phyc. Austr. Syn., No. 688. C. cruciatum, Harv. in Lond. Journ., iii., p. 449).
Thallus 10–15 cm. high, robust, irregularly pinnately alternately decompound, the whole covered with opposite di- tri- or tetra-stichous patent and generally retroflexed ramuli, which are much more crowded towards the apices of the stem or branches. The ramuli are compound or decompound, and provided usually with 4 to 6 short branchlets, and all singly or doubly mucronate. Tetraspores cruciately divided, secund on the upper sides of the ramuli. Cystocarps and antheridia unknown.
I have seen no specimens equalling in dimensions those described from Tasmania,* which are more than 1 ft. in length. Most of my specimens are tetrastichous, and distichous only when young, and I have seen nothing of the woolly filaments enclosing the base of the stem described by Harvey,† nor have I noticed the ocellated apex described for the younger specimens by Agardh.‡ However, there can be no doubt as to the authenticity
[Footnote] * Fl. Tasm. ii. 334.
[Footnote] † Loc. cit.
[Footnote] ‡ Epicr. Florid., p. 19.
of the species, as I have compared it with fragments of Harvey's original plants, with which it agrees well; and my own specimens were first identified by Agardh. I have, of course, given a description of the plants as they are found in New Zealand, and I have not adopted Agardh's or Harvey's descriptions, which were drawn up from Australian and Tasmanian specimens. The following measurements may assist in identification: Cells of rachis 500–600 μ long and 300–400 μ broad. The ramuli are from 600–800 μ long, and contain 7 to 10 cells of about 60–90 μ in length, and in breadth 30–40 μ.
5. Antithamnion plumula, Thuret (= Callithamnion plumula, Hook. and Harv., Fl. N.Z., ii., 258; J. Ag., Epicr. Florid., p. 24; Ellis, Phil. Tr. 57, p. 426).
Frond flaccid, rose-red, spreading and densely opposite pinnate, 5–15 cm. in height, the pinnæ distichous or tetrastichous, horizontal or sometimes upwardly recurved, with pectinate pinnules. In luxuriant specimens the pinnules are furnished with an additional row of pectinate subpinnules, and these again may be pectinated. Joint-cells of the axis three or four times as long as broad. The cruciately divided tetraspores in fertile specimens replace the ultimate pinnules. I have seen no description of the cystocarps or antheridia.
Varieties: (a) plumula, distichously pinnate, with the rachis and pinnules subparallel; (b) investiens, tetrastichously verticillate, with the pinnules flexuose and diverging, and enclosing the apical portion of the stem.
I have seen no specimens of the form plumula. Agardh, however, returned some specimens collected by Mr. Crosby Smith at St. Clair as A. plumula, var. investiens. This plant is epiphytic and somewhat sparingly branched, and from 1–2 cm. in length. The pinnules are apiculate and often retroflexed. To me it appears much more like a variety of A. mucronatum than of A. plumula. Agardh, speaking of the Australian form,* says that it may be a distinct species, but that he is unable to find any good distinctive characters.
Distribution.—D'Urville Island (Lyall); var. investiens, St. Clair (J. C. S.); Atlantic Ocean, Mediterranean, Australia, Fuegia.
6. Antithamnion flaccidum, R. M. L. (= Callithamnion flaccidum, Hook, and Harv., Fl. N.Z., ii., p. 258; J. Ag., Epicr. Florid., p. 20).
Thallus flaccid, 5–10 cm. long, pinnately decompound, with the larger branches and pinnæ similar and lanceolate in outline,
[Footnote] * Epicr. Florid, p 25.
oppositely pinnulate, the lower and upper pinnules of the pinnæ somewhat simple, patent, and obtuse, the middle ones compound, with the upper branchlets secund. Cells of the rachis six times longer than broad. Tetraspores in tetrads (?), secund on the pinnules.
Distribution.—Otago Harbour (Lyall); Fuegia, Tasmania.
I have seen two plants of this type, one from Riverton and one from Port Chalmers, but I cannot identify either with any certainty as belonging to this species, nor am I satisfied that the plant described by Agardh is the same as Harvey's.
7. Antithamnion (?) confusum, R. M. L. (= Callithamnion confusum, J. Ag., Epicr. Florid., p. 25. Wrangelia squarrulosa, Harv., Fl. Nov. Zel., ii., p. 236. But not Alg. Austr. exs. No. 266.)
Thallus erect, 15–25 cm. high, with rather lax irregularly alternately pinnate branches, the lower pinnæ spreading, the upper distichous with acute axils. Each node provided with whorled ramuli: two lateral ones divaricating, compound, pectinate, the branchlets of the ramulus diverging, cuspidate, often reflexed, the outer branchlets sometimes dichotomous at the tip; two smaller ramuli, often very much reduced, sometimes represented only by a hook-like process, are found alternating with the others. The ramuli do not spring directly from the node, but from a short distance below it, and are connected with it internally by a thread of brightly coloured protoplasm. Towards the base of the plant the internodes of the main axis and pinnæ are completely invested by the ramuli, which are here larger and more decompound, with many of the branchlets more or less appressed to the stem. I have only seen several sporangia, which were transversely divided into two, and, unless divided again in the plane of the slide, contained only two spores. Antheridia and cystocarps unknown.
Distribution.—Preservation Harbour (Lyall); Catlin's, St. Clair (J.C.S.); Wycliffe Bay, The Nuggets (R.M.L.).
The position of this plant is uncertain, and must remain so until the cystocarps are discovered. Harvey placed it in the genus Wrangelia. Agardh considers that its vegetative structure suggests rather the genus Callithamnion than Ptilota or Wrangelia. I believe that its place will be found in the genus Antithamnion, for it is well provided with the gland-cells (?) so characteristic of that genus, and the probably immature spores which I have seen suggest Antithamnion rather than Callithamnion. It is, moreover, very similar in structure to such a plant as A. mucronatum. There can be but little doubt of the identity of my plant with Harvey's, but it is possible that it is not the same as
Agardh's Callithamnion confusum. He states that he has seen “supra axillas quasi in gelatina effusa globos sphaericos plurimos nidulantes in quibus forsam initia antheridiorum credere licet.” Is it possible that he here refers to the gland-cells ?
8. Antithamnion ternifolium, R. M. L. (= Callithamnion ternifolium, Hook, and Harv., Lond. Journ., iv., p. 272; Flora Antarct., p. 489, tab. 189, fig. 2). Plate XXXI., fig. 2.
Thallus erect, forming dense tufts 2–4 cm. high, attached in my specimens by holdfasts to Macrocystis, rather irregularly dichotomously or pinnately branched, extremely slender and flaccid, the lower branches distant but becoming crowded towards the tip. Ramuli di- tri- or tetra-stichous, perhaps most frequently in threes, often dichotomous, flagellate, acuminate, consisting of 12–15 cells. Tetraspores cruciate, sparse, in the axils of the branches. The cystocarps are solitary and surrounded by a large number of involucral ramuli. The cells of the main stem 0.5–0.75 mm. long and 0.1–0.15 mm. wide, about five times as long as broad; cells of ramuli about twice as long as broad, and becoming rapidly narrower towards the long acuminate almost hair-like point.
Distribution.—On Macrocystis pyrifera at Timaru, in dense matted tufts (R. M. L.).
This plant has hitherto only been known from the neighbourhood of Magellan Straits. I procured specimens of it at Timaru and forwarded it to Major Reinbold, who identified it provisionally with Callithamnion ternifolium, Hook, and Harv., and this identification must hold unless it can be shown definitely that the plant is new. The specimens are much more luxuriant than those of Hooker and Harvey. Their specimens, however, were dredged, and seaweeds growing in deeper water are often dwarfed. The original description is so brief as to be almost insufficient for purposes of identification. The plate given in the “Flora Antarctica” is also not altogether satisfactory, the tetraspores being shown in one place as in tetrads, whilst another figure suggests cruciate division. The cystocarps are stated to be terminal on the branches in the “Flora Antarctica” (loc. cit.). It is not very clear what is here meant by a branch. In accordance with the generic character the cystocarps are perhaps formed at the end of the ramulus, but they are not terminal on the main stem and branches, and they become so surrounded by the involucral ramuli when fully developed that it is not easy to determine their original position. They are not two-lobed, although two are often developed close to each other. I have therefore had to rely upon the vegetative characters in determining the species. This agrees well with those described
and figured for Callithamnion ternifolium. Too much stress, however, must not be laid upon the occurrence of the ramuli sometimes in threes, for this is a common character in the genus (e.g., A. adnatum, A. cruciatum). The flagellate often once dichotomised hairlike acuminate ramuli, perhaps, therefore, in the present state of our knowledge, provide the best diagnoses for the species. Hariot mentions the plant (No. 110) in his list of seaweeds from Cape Horn, but gives no description.
(Other species of Antithamnion occur in New Zealand, but they have not yet been obtained in sufficient quantity for satisfactory determination.)
Explanation of Plates XXIV.–XXXI.
Ptilothammon pectinatum, R. M. L. (Mont.): Part of frond, showing tetraspores in tetrads, × 130).
Part of frond, showing cystocarps in various stages (x 130).
Griffithsia sonderiana, J. Ag.: Tip of branch, showing young undivided tetraspores (× 85).
Griffithsia antarctica, Harv.: Showing involucral cup with escaping tetraspores (× 45).
Pandorea traversii, J. Ag.: Tip of branch, showing involucral cup with escaping tetraspores (× 45).
Tip of frond of Pleonosporium hirtum, showing young, mature, and empty sporangia (× 85).
Tip of frond of Pleonosporium brounianum, Harv.-Gibson (Harv.), (× 85).
Tip of frond of Callithamnion colensoi, Harv., with tetraspores.
a. Small portion of ultimate pinnule of the same (× 270).
Tip of frond of Spongoclonium pastorale, R. M. L., showing division of tetraspores and (a) a mature tetraspore escaped from the sporangium (× 130).
Tip of thallus of Spongoclonium brachygonum, R. M. L. (Harv.), (× 100).
Tip of thallus of Euptilota pellucida, showing cruciate tetraspores (× 130).
Small portion of pinna of Ballia scoparia, Harv., showing characteristic spinous processes at the tips of the pinnules (× 66). for comparison with Rhodocorton parkeri (Harv.-Gibson).
Portion of a pinna of Antithamnion applicitum. R. M. L. (J. Ag.), (× 85).
Antithammon adnatum, R. M. L. (J. Ag.). Tip of the pinna (× 340). (The pinnules should be more fastigiate and less divaricating.)
Antithamnion ternifolium, R. M. L (Harv.). Tip of frond (× 340).