14. Gigartina alveata (Turn.) J. Ag. Figs. 20 (p. 128), 21 (p. 131), 45 (Pl. 15).
This is one of the original species described from New Zealand by Turner from specimens given to him by Sir Joseph Banks. It follows Fucus lividus (G. livida) in Turn. 1819, No. 239, under the name F. alveata. It has not been considered necessary in this and in other species to trace the plant through its generic wanderings in a complete synonymy. The literature is difficult of access, and for New Zealand students it will in most cases be sufficient if they begin their studies with Harvey and Agardh. Suffice it to say that after commencing with the genus Fucus, it travelled by way of Sphaerococcus, Chondrus, and Mastocarpus to Gigartina. The complete synonymic records of this and other species may be obtained by reference to Harvey and J. Agardh.
A short quotation from Turner's description, however, will probably still be of interest. Turn. loc. cit., p. 100, says, “of this, as of the preceding Fucus, may be said, that it is not only a very distinct but a very beautiful species, though one, unfortuately, of which an adequate idea can scarcely be conveyed by an engraving. The channelled structure of the frond is not, as in F. mamillosus and some others, a mere central depression, more or less conspicuous in different parts, imperfect in some specimens, indistinct in others, in all liable to variation, but it is the great and essential character of the plant,
obvious at first view, in all parts equally present, and still more decisively marked than in F. canaliculatus or F. Wrightii, whose grooved structure arises from a similar confirmation. Nor should I doubt but that, could they be found in sufficient quantity, they would make a desirable addition to our culinary menage, more so than any Fucus known to be thus employed, and probably more so than any other yet discovered.”
The plant in its typical form seems to be a purely northern type. Some specimens from Stewart Island were commented upon thus by Dr. Cotton of Kew in a letter to the senior author: “G. alveata, almost certainly. Frond is a little less channelled than usual and the copious lateral branches are not usual in our specimens. It does not however match anything else and agrees fairly well as to size.” Now the northern plant is always uniform and shows no tendency to polymorphy, and the Stewart Island plant is obviously distinct. Indeed it is probable that the Stewart Island plant may be a form of G. ancistroclada, and not of G. alveata, however, it has been too much compressed in drying to be readily identifiable. We have, however, specimens from Half Moon Bay (Stewart Island) which appear to be undoubted G. ancistroclada.
G. alveata (Turn.) J. Ag. 1851, p. 271.
Frond densely tufted 6 cm. - 12 cm. long, cylindrical at the base, and 1 mm. - 2 mm. broad deeply channelled from within 1 cm. of the base to the revolute tips (Fig. 21 b and c). The lower half of the frond naked, the upper half regularly dichotomously divided, and towards the tips flabellate. Tips thin flattened and curled outwards from the channel, with more or less spherical, not clavate cystocarps, sessile, solitary or aggregated on the convex side of the frond near the tips, and on the margins (Fig. 21 a).
On rocks between tides, at the following places:—Mt. Karioi (Raglan); Maunganui Bluff, Kaipara, Coal Point (Parenga), Whangapoa (Great Barrier), W. R. B. Oliver! Manukau Heads, R.M.L., 6 miles north of Manukau Heads, J. Turner! Muriwai, M. W. Crookes! Bay of Islands, Berggren!
15. Gigartina ancistroclada Mont. Figs. 22 (p. 128), 23 (p. 131).
This species was originally described by Montagne, Prod. ant. p. 6, and again in Voy au Pole sud. p. 121, Pl. 7, fig. 4. The latter publication only is accessible to us. The original plants were gathered at Akaroa, but we have no specimens from there and until it is rediscovered in that locality there may be some doubt as to the actual type of the species. However we have seen plants from Half Moon Bay (Stewart Island) collected by Mr. W. R. B. Oliver which correspond well with Montagne's description, and which we think must be assigned to the species. A fragment collected at Eaglehawk Neck (Tasmania) and sent to the senior author by Mr. A. H. S. Lucas under the name G. ancistroclada is very questionably the same as the New Zealand plant. More material, however, is wanted for a definite opinion. A similar but quite distinct undescribed form exists at Akatore and Stewart Island. G. ancistroclada is apparently quite a distinct species, though Harvey (1862) under Plate 197 G. ancistroclada, Mont. says: “This rare species is readily known from other Australian Gigartinas by its channelled stem and branches. In these characters it agrees with G. alveata New Zealand, but differs from this species in being pinnately decompound and not dichotomous and fastigiate. Whether mere ramification in this case be a persistent character remains to be proved. It is not impossible that the same species may appear (as often among the ferns) in a dichotomous and in a pinnated form, and I have sometimes feared that G. flabellata and G. pinnata were not permanently distinct. Should that be established,
the present plant may then be regarded as a pinnated variety of G. alveata.”
Now we have already seen that G. flabellata is a species of very questionable identity, particularly as far as New Zealand is concerned, but it certainly is not identical with G. livida. Nor can there be any question that G. ancistroclada is quite distinct from G. alveata, and if we have rightly identified them one belongs to the North end of the North Island, and the other has so far only been found from Akaroa southwards in the South Island. Our plants from Half Moon Bay agree well with Harvey's plate and with that of Montagne, though they do not show so much secund branching as in the former case, but this is a character that varies within the species in this genus (v. G. clavifera, p. 115). One noteworthy difference between G. alveata and G. ancistroclada, in addition to the difference in branching, is that in G. alveata the tips are regularly revolute, in G. ancistroclada they are curved, bent or straight, and the curving apparently may take place in any direction, sometimes back from the channel at other times towards it, sometimes over the top of the main branch, at other times away from it, and unlike G. alveata, G. ancistroclada is not regularly channelled (cf. Figs. 20 and 22). The following is the original description of G. ancistroclada from Mont. Prodr. Phyc. ant., p. 6 as quoted by J. Ag. 1851, p. 272:—
G. ancistroclada fronde hinc convexa illinc canaliculata irregulariter bi-tripinnata pinnulis oppositis vel et fasciculatis uncinatoincurvis recurvisve.
Hab. in oceano Australi ad insulam Akaroa (D'Urville).
G. ancistroclada Mont. Densely tufted, 2 cm. - 3 cm. long, stipe short 1 cm. - 2 cm. long below the first branch, in our specimens .5 mm. - 1 mm. in breadth. Branching irregularly pinnate with occasional di- or tri-chotomies, pinnae or pinnules more or less channelled, pinnules incurved or erect and somewhat flattened, often di- or trichotomous at the tips. Cystocarps globose below the tips one or several, usually within the channel. Tetraspores not seen.
Akaroa, Montagne, Half Moon Bay, Stewart Island, W. R. B. Oliver! Otago, Lyall.
The species does not appear in Agardh's list, but was according to Harvey collected by Lyall on the Otago Coast. The Tasmanian plant is quite probably distinct, but as we have only a small fragment of it, and as it is quite unsafe to identify a Gigartina without complete specimens, we prefer to leave the matter as it is.
16. G. angulata J. Ag. 1876. Figs. 24 (p. 128), 25 (p. 131), 46 (Pl. 15).
This plant was originally described from New Zealand by Bory, Voyage de la Coquille under the name Iridaea stiriata, and appeared again in 1845, London Journal of Botany IV, p. 547. In 1857, p. 277, J. Agardh transferred it to the genus Gigartina. So far it had been considered identical with Fucus stiriatus Turn. 1908, tab. 16, a plant from South Africa. In 1876, p. 197, J. Agardh, recognizing its distinctness from the Cape species established a new species G. angulata for the New Zealand form. We have seen a specimen of the Cape G. stiriata, and it cannot be doubted that our G. angulata is quite distinct. G. stiriata is placed by Agardh 1899, p. 27, under
Fig. 21. G. alveata. a × 2: Tips bearing cystocarps on convex side; b and c × 4: Sterile tips convex and channelled sides respectively; d × 8: A cystocarp.
Fig. 23. × 5. G. ancistroclada (a): Tip with two young cystocarps; (b and c): Stages in cystocarpic development; (d): A mature cystocarp.
Fig. 25. × 5. G. angulata (a, b and c): Young cystocarpic pinnules; (d): Mature cystocarpic pinna; (e and f): Sterile pinnules from lamina.
Tribe 2, Stipitatae, of his third division of Gigartina, while G. angulata is placed under Tribe 1, Alveatae. It is probably not necessary here to dwell upon the distinctions between the two tribes. G. Burmanni (C. Ag.) J. Ag. appears No. 174 Lg. 1926, p. 150, as a doubtful New Zealand species.* According to Dr. Delf 1921, p. 100, this is probably only an asexual form of G. stiriata. It may therefore now be discarded from our list.
G. angulata J. Ag. Epicr., p. 197.
Densely tufted, frond when fresh olive brown to black soft and gelatinous, particularly towards the tips. Completely flat or slightly channelled towards the upper ends, becoming still more rugose and angular on drying stipe flattened sub-cuneate, 2 cm. - 3 cm. long to the first branch. Frond usually pinnately distichously branched, rarely more or less dichotomous, earliest branching usually dichotomous, but soon becoming pinnate, the whole plant 15 cm. - 20 cm. long, breadth of stipe and primary pinnae 5 mm.- 7 mm., secondary pinnae and pinnules more or less concave on one side convex on the other lingulate to ovate, tips obtuse, in branches about to divide truncate (Fig. 24a). Cystocarps borne chiefly on rounded marginal pinnules, constricted at the base (Fig. 25d). The first cystocarp is usually terminal, secondary marginal pinnules are then formed, and bear cystocarps at their tips or laterally, finally a few cystocarpic pinnules are borne on the surface of the frond, and some cystocarps also appear more or less sessile on the secondary pinnae. In the young stages the cystocarps are sub-spherical, later becoming clavate and tubercled, owing to the development of pinnules (Fig. 25c) and the pressure of adjacent cystocarps, finally a dozen or more may be found on a branched pinnule. In tetrasporic forms (Fig. 46a) the pinnae and pinnules are flat rather broader and thinner with scattered sori throughout the substance of the frond, chiefly in the upper part.
Orepuki, W. A. Scarfe! St. Clair, J. Crosby Smith! Akatore (Tokomairiro), Moeraki, Timaru, Double Corner (near Amberley), Gore Bay, Wellington Heads, R.M.L., Shag Point, W. R. B. Oliver! Chatham Islands, The Bluff, Berggren.
This is a very distinct species, and apparently fairly uniform throughout its area of distribution. At Timaru it grows in immense masses in conjunction with forms of G. decipiens and G. clavifera on the outer side of the North Mole at low-water mark, where it has some protection from the furious seas of the vicinity, but we have seen no intermediates between it and the accompanying species. Probably its nearest relation is G. marginifera, with which it may sometimes be confused, though it is usually amply distinct.
17. G. insidiosa J. Ag. 1899.
Agardh 1899, p. 21 - p. 22, between G. canaliculata and G. angulata, proposes another species, G. insidiosa of which we know nothing, not even definitely that it belongs to New Zealand, though it may do so. We therefore quote his diagnosis and his remarks. The plant should be placed in the list of species inquirendae until more is known about it.
[Footnote] * v. J. Ag. 1899, p. 27, note.
G. insidiosa J. Ag. (1899), p. 22.
Frondes canaliculatae ramis omnibus adparenter conformibus decomposito-pinnatis, pinnis pinnulisque lanceolato-linearibus, fructiferis demum subpalmato-digitatis in disco excavato lobi infra apicem cystocarpium globosum generantibus.
Species hac tota ramificationis norma intuitu ita refert G. lividae formas juniores, quas olim nomine G. pinnatae distinguendas credidi, ut eandem hujus formam admodum angustam referre facilius quis assumeret. Accuratius vero eandem comparanti longe diversam speciem sistere adpareat. In partibus nimirum speciminis exsiccati ejusdem inferioribus detegere liceat quasi costam propriam incrassatam, quam in specie Gigartinae vix exspectandam egomet putarem. Sectione igitur facta frondis vidi hanc costam insistere partem incrassatam dorsalem frondis canaliculatae, cujus margines recognoscere licuit in aliis extra costam praesentibus. Transversali facta sectione lobi cystocarpiiferi tum dictam costam constituere regionem dorsalem frondis canaliculatae, tum cystocarpium globoso-tumidum cum aliis canaliculatae frondis inferne concretum, globoso suo apice inter parietes canaliculi liberum. Hoc modo speciem hanc tum canaliculatis speciebus pertinere didici, tum hac specie probari inter species canaliculatas alias esse generari ex dorsali jugo prominula (G. alveata), alia vero supra ventralem canaliculi regionem (G. insidiosa). Quod vero attinet G. ancistrocladam, dicere fas est, mihi non-dum contigisse ejusdem habere specimen cystocarpiis instructum.