Art. XL.—Notes on Several Species of Delesseria, One being New.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 29, 1896, Page 446

Art. XL.—Notes on Several Species of Delesseria, One being New. By Robert M. Laing, B.Sc. [Read before the Philosophical Institute of Canterbury, 4th November, 1896.] Plates XXVII. and XXVIII. Delesseria crassinervia, Mont., Voy. au Pôle Sud. Hooker, in his “Handbook of the New Zealand Flora,” p. 683, amongst other species of Delesseria, includes D. crassinervia, originally described by Montagne (Prodr. Ant., p. 3), but afterwards more fully described and figured by the same writer in Voy. au Pôle Sud: Botanique, vol. i., p. 164, and tab. 8, fig. 1. In the Handbook the New Zealand habitats of the plant are given as the Auckland and Campbell Islands, and also, on the authority of Lyall, Ruapuke Harbour and Stewart Island. Montague's plant came from the Auckland Islands. J. G. Agardh, on the other hand (“Epicrisis Floridearum,” pp. 490 and 492), discards the specific name crassinervia from his list of recognised species, retaining it only in a foot-note with Montagne's original description attached. He, however, describes, on his own authority, a species, D. montagneana, which he doubtfully considers—and erroneously as I believe—to be D. crassinervia, Mont.; and he also states—again erroneously—that Hooker's plant is not entitled to its specific name, as it is different from Montagne's. He himself does not adopt the specific name crassinervia, as he considers his plant differs in some important details from the description given by Montagne (Prodr. Ant., p. 3). He considers it safer to redescribe his species under the new specific name—i.e., D. montagneana. The D. crassinervia of Harvey (i.e., of Hooker's Handbook) he refers to a new species, D. phyllophora, remarking that apparently several species have been confounded under the name D. crassinervia. Now, I wish to show—(a) That we have in New Zealand D. crassinervia, Mont., and that the specific name must therefore stand; (b) that D. crassinervia of the Handbook probably includes two species, one of which is the true D. crassinervia; (c) that apparently Agardh has not seen D. crassinervia, Mont., and consequently has endeavoured to assimilate it to several other species, and that therefore he is quite in error in his attempt to explain away the specific value of the name. (a.) Montagne's specimen was apparently an old one, or

else a winter form; but I have had in my collection for several years a specimen from the Mongonui Beach, at the Chatham Islands, which agrees in all points of specific value with the figure of Montagne, and with the descriptions both of Montague and Harvey. I append a description of the plant. During the Christmas holidays of last year I collected the same species amongst the drift-weed at St. Clair, and afterwards, in company with Mr. J. Crosby Smith, I obtained it growing epiphytically on Carpophyllum, at Wycliffe Bay, Otago Peninsula. (b.) The description given in the “Handbook of the New Zealand Flora,” although very imperfect, agrees almost perfectly with the specimens I have collected; but the following instructive note occurs in Agardh's “De Algis Marinis Novæ Zelandiæ,” p. 25, under the name D. montagneana: “Specimina D. crassinerviæ, Harv., nulla e N. Zelandia vidi, ex insulis Falkland, manu ni fallor Harveyi nomine D. crassinerviæ inscripta, me judice ad speciem admodum diversam pertinent, quam D. phyllophoræ nomine descripsi.” Now, as it is quite clear from the description of D. crassinervia and D. phyllophora (J. Ag., Bidr. Fl. Syst., p. 55) that they are distinct plants, and if Agardh is right in supposing that his specimen of D. crassinervia from the Falklands is inscribed in Harvey's handwriting, it is quite clear also that the latter has confused two distinct plants under this name. Be this as it may, it does not in any way interfere with the validity of the species D. crassinervia, and is only introduced here in order to avoid, if possible, subsequent confusion and misconception as to the limits of the species. (c.) Agardh, while not definitely rejecting the species D. crassinervia, doubtfully splits it up into three—viz., D. phyllophora, J. Ag., D. montagneana, J. Ag., and D. epiglossum, J. Ag.—and hesitatingly admits the possibility of a fourth, the true D. crassinervia, Mont. I expect Agardh's three species are genuine, but they are certainly distinct from my plant, and not D. crassinervia. As I have already explained, D. montagneana is intended to replace doubtfully D. crassinervia, Mont.; D. phyllophora is D. crassinervia, Harv. (from Falkland Islands), but it is not at all clear to me why he should consider D. epiglossum as possibly in part equivalent to Harvey's plants, unless he doubted the accuracy of the description given in the Handbook. It now only remains to show how the three species mentioned above can be readily distinguished from my plant, which is, I believe, the true D. crassznervia, Mont.; and this is easily done. Indeed, the following note from Agardh, taken in conjunction with the one already quoted, not only does this for us, but clearly explains how all the confusion has arisen:—

(“Epicrisis Floridearum,” p. 493.) D. montagneana: “Sunt in magnitudine et ramificationis norma hujus multa, quibus cum D. crassinervia, Mont., convenire videtur. Obstat vero quod de microscopicis venis, admodum conspicuis in nostra, nullum verbum, habet Montague. Suam plantam evidenter senilem, et lamina in pluribus ramis derasa forsan hyemalem, cujus in frondibus juvenilibus paucis venæ parum conspicuæ adessent, credere propensus fuissem, nonnullas tamen, frondes lamina instructas vidit et depinxit; venasque in his, si adfuissent, ab eo prætermissas fuisse eo minus assumere fas est, quam jam tunc temporis præsentiam aut defectum venarum characteres cujusdam momenti in speciebus proximis dignoscendis præbere cognitum fuit.” The absence of transverse venation in Montagne's plant is evidently, then, the stumbling-block that prevented Agardh from discarding altogether the specific name crassinervia; but there are no transverse veins microscopic or macroscopic in my specimens, and this at once separates it from D. epiglossum, D. phyllophora, and D. montagneana, and gives an additional reason for regarding it as the true D. crassinervia. It also differs from them in many other points of habit, size, &c.; but upon these I need not dwell. From the following description it will be seen that the plant must be placed under Agardh's sub-genus Hypoglossum:— D. crassinervia, Mont. Root a small disc. Main stem flat, corticated, costate to the tips, narrowing somewhat towards the disc, originally bordered with a wing 3mm.—4mm. wide, which disappears in the older plants, leaving only the broad costa 2mm.-4mm. wide. Costa of pinnæ and pinnules similar to that of the main stem, and also narrowing somewhat towards the point of insertion. Frond a bright lake-red extremely thin and flaccid, decomposing rapidly but retaining its colour well if dried when quite fresh, 25cm.-40cm. long, general outline linear, oblong-ovate, or broadly elliptical or irregular, as the pinnæ and pinnules do not develope in acropetal succession; irregularly bipinnately or tripinnately compound. Pinnæ and pinnules proliferous winged, but giving the appearance of a distichous frond owing to the abrasion of the lamina, costated to the tips, but not otherwise veined. Pinnæ 10cm.-15cm. long, pinnules 2cm.-4cm. long, linear-acuminate, bearing proliferous sporophylls, which are developed singly on each side of the costa and on both sides of the lamina. Sporophylls 3mm.-4mm. long, linear or ovate, slightly stipitate, costate to the tip,* The costa is externally evanescent, but the costal cells can be traced to the tip with the microscope. Vide D. linearis. but not otherwise veined, microscopically and irregu-

larly serrulate, bearing in two oblong patches on either side of the costa numerous irregularly-arranged tetraspores of the usual type. The tetraspores are not confined to the sporophylls, but are also found below the apices of the pinnules, where the sporophylls are absent. Cystocarps not seen. Hab. St. Clair, Dunedin; Wycliffe Bay, Otago Peninsula; Mongonui, Chatham Islands! (Ruapuke Harbour and Stewart Island: Lyall. Lord Auckland Group and Campbell Islands: Sir J. D. Hooker.) Delesseria linearis, sp. nov. I have had for some time in my possession what is apparently a very distinct species of Delesseria, not yet described. I have found it at Lyall's Bay on two occasions only, once growing on a Coralline, and on the second occasion epiphytic on Pterocladia. It is apparently rare. On account of its shape I propose to call it D. linearis. The species is remarkable for the complete disappearance of the costa about one-third of the way up the frond. Agardh, in his description of the genus (“Epicrisis Floridearum,” p. 478), states that, “in those species in which the costa is more or less obsolete and evanescent externally, the costal cells are nevertheless rather frequently continued to the tip. In these species the whole longitudinal increase in length of the frond is seen to depend upon the evolution and subdivision of these cells.” This is the case with D. crassinervia, in which the costa becomes externally obsolete a few millimetres from the apex of the frond; but the longitudinal row of cells of which it is formed may be traced to the growing point, where they terminate in a single cell. In D. linearis, however, the costa disappears completely about one-third of the way from the base of the frond, and there is beyond that point no differentiation of the parenchymatous cells. However, a terminal cell is readily seen, and below it the cells are flabellately arranged, evidently as a result of its division. In other respects the plant conforms to the normal type of the genus. Hab. Lyall's Bay, Cook Strait. Description of species: D. linearis, sp. nov. Frond simple, linear sessile, narrowed towards the base, epiphytic, 40mm.- 50mm. long, 4mm.-5mm. broad, apex obtuse, margin entire. Costa indistinct, disappearing one-third of the length of the frond from the base, otherwise without veins. Sporophylls arranged in acropetal succession up the centre of the frond, generally singly (but two or three sometimes spring from one point, and sometimes secondary sporophylls of similar character arise from the backs of the primary ones), suborbicular, emarginate, and slightly stipitate, 1mm.-2mm. in diameter. Numerous tripartite tetraspores occupy the whole surface of

the sporophyll, excepting the narrow outer margin. Cystocarps not seen. D. lancifolia, var. minor, n. var. Owing to the kindness of Mr. A. Hamilton, of Otago University, I have received a few fragments of seaweed, collected by him at the Macquarie Islands. Amongst these is a Delesseria, which I find myself unable to distinguish specifically from D. lancifolia (J. Ag., Bidr. Fl. Syst., p. 59). Harvey regarded this latter plant as merely a variety of D. sanguinea; but Agardh, who has, however, only one fertile specimen of the plant, considers it a distinct species. My plant differs from Harvey's in being very much smaller, and unbranched, and apparently, also, in bearing sori only on the sporophylls. None of these points, however, may be constant, and so I do not think it necessary at present to describe it as a fresh species, but have assigned to it the varietal name minor. Hab. Macquarie Islands. Description of variety: D. lancifolia, var. minor. Frond simple, linear-lanceolate, acuminate, sinuous, stipitate, 30mm.-40mm. in length, 4mm.-6mm. in breadth, with distinct midrib and pinnate nerves, which extend two-thirds of the way to the margin. Sporophylls similar in type to the frond, 3mm.-4mm. in length, springing from both sides of the costa, solitary or fascicled, stipitate and provided with a distinct midrib but without lateral veins. The tetraspores are arranged longitudinally on either side of the costa. Cystocarps not seen. I have deposited type specimens of the three above plants in the Canterbury Museum. No list of Algæ from Macquarie Island, has, so far as I know, been published. With the plant above described, I received from Mr. Hamilton a number of other specimens, most of which were, however, too fragmentary for adequate determination. It may be of interest to note that there were amongst them, in addition to the above variety, Ballia callitricha, Melobesia antarctica (?), Plocamium, 2 sp., Polysiphonia, sp., Delesseria, sp. Explanation Of Plates XXVII. And XXVIII. Plate XXVII. Delesseria crassinervia, Mont. (Photograph from Chatham Island specimen.) Plate XXVIII. Fig. 1. Delesseria lancifolia, var. minor, mihi, X 4 diam. Fig. 2. Delesseria linearis, mihi, X 2 diam. Fig. 3. Sporophylls— (a.) D. crassinervia, X 15 diam. (b.) D. linearis, X 15 diam. (c.) D. lancifolia, var. minor, X 15 diam.