The New Zealand Species of Gigartina.
[Read before the Philosophical Institute of Canterbury, December 5th, 1928, received by Editor, December 20th, 1928; issued separately, 31st May, 1929.]
The family Gigartinaceae includes a number of genera of which perhaps ten are to be found on the coasts of New Zealand. Of these the most abundant, both in the number of species and in quantity, is Gigartina. Immense masses of members of this genus frequently fringe the rocks on more or less exposed coasts about low-water mark. Elsewhere many species of the family have been found to have some economic value; but so far little use of them has been made commercially in New Zealand. Thus carageen (Irish Moss), a favourite remedy for colds, is prepared in quantity from Chondrus crispus and Gigartina mamillosa; and though we have neither of these species in New Zealand, yet we have others so closely allied to them, that no doubt they could be similarly employed. Indeed they have frequently been so employed locally, but so far do not appear to have entered the commercial world. Carageen could doubtless be made from Gigartina protea, G. angulata, G. clavifera and similar species. Species of the genus are elsewhere used for the manufacture of size, as a food, for jellies (used in making lollies, etc.) and in other ways. No doubt if economic conditions warranted, they could be similarly used in New Zealand. Their value consists in the amount of gelatine (gelose) which they contain. This is readily obtained by washing and boiling the plants in water, when a translucent mass, solid when cold, is obtained. This has remarkable thickening properties, and is used as a stiffener for imitation silks, muslins, nainsook, etc. There is little doubt also that agar-agar used as a culture for bacteria could be prepared from species of Gigartina, though at present chiefly obtained in India and the far east from species of Gracilaria and Gelidium. However, the algal harvests procurable from our sea coasts have yet to be recognised.
The family as at present constituted is due to F. Schmitz and P. Hauptfleisch (1897), p. 352, but the genus Gigartina was first proposed by Lamouroux (1813) Ess., p. 48, As defined by him it contained plants now widely separated. Some species of Chordaria were
even included in it. In its present form the limits of the genus are practically those proposed by J. Agardh in his later writings. Though subsequent definitions by other authors in terms of the carpogonial organs, differ much from his in form, they still include the same species, and his arrangement of the species will be largely adopted here. Agardh 1899, p. 6, points out the extreme diversity of form in some of the species, and states that even Kuetzing placed sterile, tetrasporic, and cystocarpic forms of the one species in different genera. It is obvious therefore that if possible all three forms should be described. Some species, however, are sufficiently distinct to be identified from imperfect specimens. Thus G. Chapmanni (Pl. 2), the second on our list, was described from a single sterile plant, but there can be no doubt as to its identity. Apparently the tetrasporic form is still unknown. Unfortunately as the internal structure of the frond and of the cystocarps do not usually afford sufficient characters for identification of the species, their differentiation has to depend chiefly upon branching, form and consistency of the frond, and arrangement and external characters of the cystocarps. As all of these may be polymorphic in one species under different habitat conditions, as there may also be hybridisation between similar species (cf. Barton, Jour. of Bot. May and Nov. 1896) the difficulties in the accurate definition of the species are great, and no one character can be relied upon to distinguish adjacent species, and often it is quite impossible to say under which name a single specimen is to be placed. However by comparison of a large number of specimens they can be grouped into different and generally distinct sets. The type species is Gigartina pistillata (Gm.) Lam. but this represents a form of frond which is not very characteristic of the majority of the species. Harvey identified a New Zealand form as G. pistillata, but unfortunately his descriptions are often so wide and imperfect, that they would apply to several different species. The subsequent descriptions of J. Agardh are generally sufficient for identification, but it is by no means clear that Agardh correctly recognised in all cases the form described by Harvey. We have had the good fortune to see a number of specimens identified by Agardh, but none of Harvey's is available in New Zealand. Unfortunately neither Agardh nor Harvey ever visited New Zealand, and were dependent upon visiting collectors, and under these circumstances it is certainly to be expected that they would fall into error in the delimitation of some species. Writing of the Florideae in general, the senior author (1926, p. 129) points out that “In some genera at least the number of species will have to be reduced. Fragments of the same species, showing in some cases polymorphic differences have been described as different species. This is true at least in the genera Gigartina, Plocamium, and Nitophyllum, and probably in other groups.” Now while it is correct that certain species of Gigartina will have to be reduced to synonyms, yet there are undescribed species, so that the total number given (29) loc. cit. is less than the actual number existing on the coasts.
It is hoped in this paper by the aid of descriptions, photographs and diagrams, to provide means for a more accurate identification of the forms existing in New Zealand. As the number of species is large (over thirty) it will be necessary to divide the work into more
than one part. The first appears here. Unfortunately little collecting has been done on the West Coast of New Zealand, so this paper is practically an account of the East Coast Gigartinas, and those chiefly of the South Island.
For the purpose of identification in the field and in the herbarium, it is not usually necessary to follow the development of the carpogonial organs, and as to do this would present many difficulties, the easier course of defining the species from the fully mature plant has been adopted here. The following description of the genus therefore will probably be sufficient for our purposes.
Genus Gigartina.—Thallus cylindrical, flattened or foliose, usually thick and fleshy, corneous when dry, more or less profusely pinnately, dichotomously or irregularly branched. Usually beset with fertile ramuli of limited growth, bearing the cystocarps, simple or branched, growing from the margin of the branch or from the surface of the lamina. Cystocarps on the fertile ramuli, singly or in more or less dense clusters, usually spherical or approximately so, and partially embedded in the tissue of the ramulus, sometimes surrounded by an adnate involucre of ramuli, or surmounted by one or more linear processes. Nucleus compound and surrounded by a net work of filaments. Structure of two tissues, the inner of anastomosing threads loosely woven into a net, and passing into the outer cortical layer of moniliform vertical filaments, imbedded in firm gelatine. Tetraspores numerous in subprominent sori, below the superficial stratum, cruciately divided.
Agardh (1899), pp. 1–42, lists and classifies sixty-nine species, and in this paper we shall follow to a large extent his classification, though it is not altogether satisfactory. The genus is exceptionally well-developed in New Zealand, which contains more than a third of the species listed, and many of these are endemic. It is possible, as has been suggested, that the genus should be split up into several genera, but though many of the species are highly polymorphic, yet all exemplify the general characters as given above. In this paper we exclude all forms with broadly expanded laminae.
The following classification is based on that of Agardh, but considerably modified.
Division A.—Frond partly or altogether cylindrical.
Tribe 1.—Cylindratae. Frond cylindrical throughout or in part slightly compressed, pinnately decompound.
1. G. divaricata Hook. f. et Harv.
Tribe 2.—Aciculares. Thallus sub-terete, more or less decompound, quadrifariously branched, terminal branches subulate, fertile ramuli unaltered, cystocarps lateral on the pinnae or the genuflexed fertile ramulus.
2. G. Chapmanni Hook. f. et Harv.
3. G. Kroneana Rabenh.
Tribe 3.—Pistillatae. Sterile frond somewhat rounded below at least, more or less evidently dichotomous and decompound with the
branches produced to a point, margins of fertile branches beset with the cystocarpic pinnules, generally opposite, with the cystocarps few or many globose, or clavate sometimes subsecund along the upper margin of the pinnule, becoming apparently terminal by the abortion of the apex of the ramulus.
4. G. macrocarpa J. Ag.
5. G. clavifera J. Ag.
(G. disticha Sond. species excludenda).
6. G. flabellata J. Ag.
Division B.—Thallus compressed or flat, branching normally dichotomous, but sometimes decompoundly pinnate, the position of the cystocarps varying according to the mode of development of the frond.
Tribe 1.—Palmatifidae. Frond flattened almost from the base, and with decompound segments going out from the margin, the primary sub-dichotomous, the lowest more elongated, the uppermost reduced, with the lobes of the latter cuneate rotund, diverging, sub-palmately; the cystocarps occupying the unaltered terminal ramuli, sub-singly behind the apex of the lobe.
7. G. laciniata J. Ag.
Tribe 2.—Pinnatilobae, with the frond above the lowest part compressed, flattened, pinnately decompound, lobes sometimes developed to a point but more often obtuse, cystocarps occupying the terminal unaltered ramuli, sub-singly behind the apex of a lobe.
Tribe 2.—Pinnatilobae, with the frond above the lowest part compressed, flattened, pinnately decompound, lobes sometimes developed to a point but more often obtuse, cystocarps occupying the terminal unaltered ramuli, sub-singly behind the apex of a lobe.
8. G. livida (Turn.) J. Ag.
Tribe 3.—Prolificantes. Frond above the lowest part compressed flattened and the branches generally drawn out into a point, the whole usually more or less dichotomously decompound (though pinnated at times), the fertile ramuli emerging from the edge of the frond or from the surface of the lamina. Cystocarps sub-single to numerous behind the apex of the ramulus, which is simple or branched.
9. G. protea J. Ag.
10. G. marginifera J. Ag.
11. G. polyglotta J. Ag.
(G. volans C. Ag. A foliose form, not further dealt with here).
12. G. decipiens Hook. f. et Harv.
Tribe 4.—Innocuae. Frond pinnately decompound and distichous, pinnae sometimes narrow and linear, sometimes more dilated, lanceolate flattened, cystocarps papillose in the disc of the pinnae, sometimes singly at the apex of the pinnae which overtops it or by disappearance of the tip, terminal, or many in an elongated, branched, often crooked ramulus.
13. G. Chauvinii (Bory) J. Ag.
Division C.—Without special fertile ramuli, and with the frond on one side more or less channelled or concave on the other angular or convex, sometimes teretely stipitate below, the upper part more or less expanded, the position of the cystocarps varying with the mode of branching.
Tribe l.—Alveatae.The frond channelled with all parts more or less similar, the lower and uppermost almost equally narrow linear, the apices sometimes obtuse, sometimes produced into a point.
14. G. alveata J. Ag.
15. G. ancistroclada Mont.
16. G. angulata J. Ag.
(G. Burmanni (C. Ag.) J. Ag. Species excludenda).
17. G. insidiosa J. Ag.
Tribe 2.—Stipitatae. Frond above the somewhat terete base, somewhat expanded into cuneate segments, bearing the cystocarps on the concave side.
18. G. tuberculosa Rabenh.
Description of Species.
1. Gigartina divaricata Hook. f. et Harv. 1845 (but not of J. Ag.)
Fig. 1 (p. l08), 27 (Pl. 5), 28 (Pl. 6).
Harvey' original diagnosis was made from a few imperfect sterile specimens washed ashore on a beach at Campbell Island. It runs as follows, Hook. f. et Harv. (1844–1847) I. p.187.
“G. divaricata, Caule cartilagineo-carnoso compresso lineari sub- dichotome diviso, ramis distichis pinnatisve sub-pinnatis, ramulis linearibus sub-attenuatis.”
In a more detailed account given below the diagnosis, the following occurs:—Caulis 4–6 unc. longus, sub-dichotome divisus, 1–2 lin. latus, compressus, strictus, ramis subquadrifariis, distichisve dense obsitis, Rami divaricati stricti compressi, rugulosi, nudi, parce pinnati v. sub-pinnati apicibus longis, nudis. Pinnulae horizontales breves, simplices vel furcatae, lineares acutae, nunc abbreviatae et spini formes, color lividus v. nigro-rubescens, ad apices ramulorum pallidior purpurascens.“
Now among the specimens of marine algae collected by Messrs. J. Crosby Smith and R. M. Laing on the. trip of the Hinemoa to the Sub-Antarctic Islands of New Zealand in 1907 was a remarkable Gigartina found both at the Snares and at Campbell Island. This was amongst the specimens sent home to Mr. A. Gepp at that time in the Cryptogamic Department of the British Museum. He marked it first as near G. disticha or G. divaricata, but finally identified it as G. divaricata. Under this name it was recorded in the ‘sub- Antarctic Islands of New Zealand’ Chilton, 1909, p. 505. A further examination confirms this identification, though it must be admitted that there are certain difficulties in establishing it.
There can be little doubt that it is not G. disticha Sond. a Western Australian plant, whose occurrence or non-occurrence in New Zealand will have to be considered more fully shortly; and it is probably not worth while here contrasting our plant with the West Australian one; but the difficulties in connection with its identification as G. divaricata Hook. f. et Harv. must be considered.
The first point to be noted is that Harvey after describing G. divaricata as a new species revoked his decision, and included the plant with various other forms in the European G. pistillata (Gm.) Lam., and came to the conclusion that in New Zealand G. pistillata was a very variable plant, and that transition forms could be found between forms widely differing in appearance, J. Ag. 1876, p. 195 (note) rejected and as we think quite rightly the identification of any New Zealand species with G. pistillata, and re-established the G. divaricata Hook. f. et Harv. However it is quite clear to us that the G. divaricata of J. Ag. is not the original plant, but a different species altogether, indeed merely a form or state of the plant that Agardh himself described as G. decipiens Hook. f. et Harv. or possibly G. clavifera J. Ag.*
This matter will be more fully discussed under the latter species.
It remains now to show that our plant is probably the original G. divaricata Hook. f. et Harv. Both plants have the same place of origin. Further we have received from Dr. Cotton of the Kew Gardens a drawing of one of the co-types of G. divaricata, and this corresponds well with some of our specimens, it has the same stout rigid central stem, and is distinctly pinnately branched. This specimen would no doubt have been available to Mr. Gepp in making his identification of our plants, and on these grounds alone it is probably fairly safe to conclude that our plant is the same as Harvey's. But when we come to Harvey's diagnosis, we find various discrepancies in his description, when compared with our specimens. These are probably to be accounted for by the fact that Harvey had incomplete sterile plants to go upon, whereas our specimens though not numerous are fairly complete and cystocarpic. Harvey states that his specimens are compressed, distichous and sub-dichotomously divided. Our plants are very slightly compressed and they are distinctly pinnate, though occasional apparently dichotomous branching may be met with, and they are not altogether distichous. It should, however, be noted that Harvey in his subsequent description practically alters his original account and describes the plant as we have it. Though retaining the “sub-dichotome,” he modifies the “distichis,” with “sub-quadrifariis,” and in both descriptions he states the branches are pinnate or sub-pinnate. The only point on which we can now differ is as to the amount of compression, and on this point Harvey's description is not sufficiently detailed. Our specimens are only very slightly compressed in the plane of the chief branching, and possibly this is all that Harvey meant. Taking all things into consideration it seems very probable that our plant is Harvey's original G. divaricata, a species apparently confined to the southern islands of New Zealand.
Gigartina divaricata Hook. f. et Harv.—G. pistillata (Gm.) Lam. partim of Fl. Nov. Zel. ii., p. 251.
A very stout rigid, cartilaginous plant, branches throughout cylindrical, distichous or sub-quadrifarious with the main branches slightly compressed in the plane of the branching. Branching irregularly pinnate, to tri-pinnate, ocasional examples of apparent
[Footnote] * We have seen only two specimens of G. divaricata J. Ag., and they are too fragmentary for certain identification.
dichotomy of a branch may be found. The main stem is 15 cm. - 20 cm. long, strict or slightly bent and twisted, 4 mm. - 5 mm. in diameter. Primary pinnae varying in length and arrangement 2 cm. - 12 cm. long, alternate or several in succession from one side, naked or again much branched. Secondary pinnae 3 mm. - 4 mm. in diameter terminal pinnules 1 mm. diam., cystocarps large 1 mm. - 1.5 mm. in diam. terminating ramuli 1 cm. - 2 cm. long on the main branches,
solitary at the ends of the ramuli, or aggregated, sometimes lateral, the ramulus simple or very sparingly branched. (Figs. 27, 28). Tetrasporic plant not seen. Cystocarpic specimens in November.
The species is well marked off from all others in New Zealand by its cylindrical branches, extreme stoutness and rigidity, and the fairly uniform thickness of the main stem and branches.
Monument Harbour, Campbell Island and The Snares. R.M.L. and J.C.S. (Campbell Island, J. D. Hooker).
2. G. Chapmanni Hook. f. et Harv. Figs. 2 (p. 110), 3, 4 (p. 113), 29 (Pl. 6).
This species is placed by Agardh in his group aciculares with cylindrical fronds, yet though always cylindrical at the base, and sometimes so throughout, at other times it becomes flattened on branching. It is apparently closely related to the European G. acicularis, of which we have seen no specimens. In other forms it closely approaches the Tasmanian G. Binderi, placed by Agardh in division B., tribe 2 Pinnatilobae. We have only seen a fragment of G. Binderi from which however our plant is probably distinct, but that cannot be fully determined without a series of specimens of both plants.
G. Chapmanni Hook. f. et Harv. Fl. N.Z. ii, p. 251, tab. 119 B.
The base is a more or less oblong or circular disc a few mm. in diameter closely appressed to a shell or rock. From it there arises a dense and intricate mass of fronds. The branching is various, chiefly irregularly pinnate, more occasionally dichotomous, generally quadrifarious (Fig. 2). The primary pinnae are 8 cm. - 10 cm. long and about 1 mm. in breadth. The secondary pinnae are usually alternate, sometimes opposite. Frequently several appear in succession on one side, they vary much in length 2 cm. - 5 cm. and are .5 mm. - 1 mm. in breadth. They are again provided with numerous acicular pinnules simple or forked, 2 mm. - 5 mm. in length, all the terminal branchlets being acicular or subulate, generally slightly constricted towards the base and compressed in the middle. More flattened forms, scarcely distinguishable from G. Binderi Harv., with the pinnae distinctly flattened 2 mm. wide have been found at Akaroa and Lyall Bay; small globular naked cystocarps less than a mm. in diameter are developed sparsely on the pinnae, more rarely on the genuflexed pinnules (Fig. 4), sessile usually one to four on either side of the pinna close together, more rarely solitary terminating a pinnule. Tetrasporic plant unknown. Maketu (Bay of Plenty, Chapman); Petone, Lyall Bay, Sumner, Lyttelton (Purau and Governors Bay), Akaroa, R.M.L.
The plant apparently grows most abundantly in shallow sandy or muddy bays, a few feet below low water mark attached to pebbles and shells. It can scarcely be called common. Its range so far as is at present known is from the Bay of Plenty to Akaroa. Cystocarpic specimens were obtained at Purau in July. It occurs throughout the winter months, and may not be an annual. The carpospores often escape from the cystocarp in pairs and occasionally in fours, suggesting the division of a single gonimoblast cell into two or four.
3. Gigartina kroneana Rabenh. Fig. 5 (p. 111), 30 (Pl. 7).
This is a little known species, not mentioned by Agardh and either excluded or overlooked by him. We have specimens collected by the senior author on the Hinemoa trip at Campbell Island. Unfortunately they are sterile, and though the structure is that of
Fig. 2. × 2. G. Chapmanni. Portion of rachis showing branching, disposition and forms of pinnae.
Fig. 6. × 2. G. macrocarpa. Portion of tip of cystocarpic plant.
Fig. 11. × 2. G. livida. Tip of shortened cystocarpic form.
Fig. 13. × 2. G. protea. Semi-juveniie cystocarpic form.
Fig. 15. × 2. G. marginifera. Tip of young plant with cystocarps.
a typical Gigartina, without the cystocarps it is impossible definitely to determine the genus. The specimens were sent to Mr. Gepp then of the Cryptogamic Department of the British Museum, who identified them thus, “G. Kroneana, apparently. No authentic specimens
seen by me.” They are so recorded in Sub-Antarctic Islands of New Zealand 1909, p. 506, where the original description of Rabenhorst is quoted. There the cystocarps are stated to be, “sub-globoso-capituli-formibus, singulis in ramellis ultimis.” The plant will obviously have to be placed in Agardh's section Aciculares.
Fig. 17a. × 2. G. decipiens. Tip of sparingly-branched form of Plate 14.
Fig. 17b. × 2. G. decipiens. Tip of richly-branched form of Plate 15.
Fig. 17c. × 2. G. decipiens var. semi-palmata. Tip showing palmate form.
Fig. 5a. × ½ G. Kroneana, with leaf-like, lighter coloured tips.
Fig. 5b. × 2. G. Kroneana; d.p. developing pinnae.
G. Kroneana. Our specimens are 25 cm. - 30 cm. long, dark red when collected, now black, sparsely irregularly pinnately quadrifariously branched, with occasional dichotomies sometimes three or four branches spring quadrifariously from one point, the main branches sub-terete, secondary branches flattened (but terete and
acicular in fresh specimens. Fig. 5a), all in dried specimens 2 mm. - 3 mm. in diam. The branchlets originate in the interior of the stem, an aperture appears through which a papilla protrudes, from which the branch develops (Fig. 5b). The apices sometimes terminate in one or more linear leaflets several cm. in length (Fig. 5a) or are sometimes knobbed at the ends. The stems and branches in the dried specimens are rugose and more or less twisted. Length of segments between branches very variable 2 cm. - 15 cm.
Drift-weed and rocks, Monument Harbour, Campbell Island, R.M.L.
As Rabenhorst's original diagnosis is difficult of access I quote it here from Hedwigia XVII (1878), p. 70. The article is entitled “Beitrag zur Meeresalgenflora der Auckland Inseln.”
“Gigartina Kroneana, Rabenh. nov. sp. Vage ramosissima, durissima cornea, dilute vel obscure brunnea, stipite e basi dilatata ramis ramulisque 2 - 4 millim. latis, tereti compressis ramulis ultimis (ordinis tertiae vel quartae) subulatis nunc brevibus nunc elongatis (ad. 3 cm. longis) rectis vel plus minus curvatis, axillis obtuse angularibus, cystocarpiis sub-globoso capituli-formibus, singulis in ramellis, ultimis.”
4. Gigartina macrocarpa J. Ag. 1876. Figs. 6 (p. 110), 7, 8 (p. 113), 31 (Pl. 8).
In this division are placed those species that to some extent resemble the European G. pistillata; and were described as already pointed out, no doubt erroneously, by Harvey under that name. The first on Agardh's list is G. macrocarpa J. Ag. We have seen some of the original specimens of Agardh and have no doubt of its identity or distinctness. It seems to be a purely northern form as we have seen no specimens south of Manukau.
G. macrocarpa J. Ag. Epicr. Florid., p. 683.
Fronds numerous 3 cm. - 12 cm. long, arising from a disc, more or less regularly dichotomously and pinnately branched, maximum width very variable 1 mm. - 4 mm. In sterile fronds the branching is usually fairly regularly dichotomous. The extreme base for a few mm. is cylindrical, and then becomes flattened, expanding to its maximum breadth before it divides dichotomously, terminal pinnules obtuse to sub-acute. Fertile fronds are densely covered with lateral ramuli, of very variable length 1 cm. - 4 cm. simple or branched, similar in form to the pinnae. On these are developed the naked cystocarps in few or in large numbers aggregated or separate. In luxuriant forms the fertile ramuli are again pinnulate. The cystocarps sometimes develop behind the terminal pinnule and so are at first apiculate, but they become terminal by the loss of the ultimate pinnule (Fig. 8, a-f). In some cases a lateral acicular process develops immediately below the cystocarp (Fig. 8c). The lateral cystocarps at first sessile, become in the course of development shortly stipitate. They are most frequently lateral, but occasionally one may be found developed from the surface of the somewhat flattened pinnule.
According to Agardh (loc. cit.) the sterile and fertile portions are very different. The sterile is more cylindrical, thinner than the
common form of G. pistillata, and indefinitely quadrifariously branched. In the fertile fronds the pinnae become more dilated. Tetrasporie forms (not seen by us) have the branches narrower than those of the cystocarpie plants, with the sori in long lines, sometimes in both margins of the segments between the pinnae, and sometimes in the pinnae themselves. Mature cystocarps barely 1 mm. in diameter.
Fig. 3. × 5. G. Chapmanni (a, b and c): Tips of pinnae; (d and e) Regeneration tips.
Fig. 4. × 5. G. Chapmanni (a): Cystocarpic pinna with typical genuflexious at the cystocarps; (b) Portion of rachis showing attachment of pinnae.
Fig. 7. × 6. G. macrocarpa (a and b): Tips of pinnae; (c) Regeneration tip.
Fig. 8. × 6. G. macrocarpa (a-f): Showing development of cystocarpic pinnae.
Bay of Islands (Berggren), Waipu Cove (Mrs. T. Maidment!), six miles north of Manukau Heads (J. Turner!).
In 1909, p. 506, the senior author recorded G. macrocarpa J. Ag. from the Snares, following A. Gepp. The plant so described is not G. macrocarpa, but a form of G. clavifera J. Ag. under which it is described as G. clavifera var. tortuosa.
5. Gigartina clavifera J. Ag. 1876. Figs. 9, 10 (p. 116), 32 (Pl. 8), 33, 34 (Pl. 9), 35 (Pl. 10).
This species was described by J. Ag. 1876, p. 194, to replace in part the G. pistillata of Harv. in Fl. N.Z. ii, p. 251. It is separated from G. pistillata (Gm.) Lam. by the clavate not spherical cystocarps (“at ramulis fructiferis diversis fere claves belligerantium, a ligno confectas, in insulis Australsic., olim usitatas forma referentibus”). Agardh here places the species in his group excipulatae (pinnellae fructiferae lobis subtransformatis ambientibus munito, quasi umbilicatis), i.e., the cystocarps are surrounded by an irregular involucre of pinnules. In this group he places G. clavifera, G. flabellata, G. disticha, and G. divaricata. Of these G. clavifera is a remarkably polymorphic species. G. flabellata and G. disticha are both Australian species doubtfully occurring in New Zealand, and G. divaricata of Agardh as we shall now endeavour to show is merely a synonym for G. clavifera J. Ag. or G. dicipiens of J. Ag. The following are the differences between G. clavifera and G. divaricata J. Ag. as described loc. cit. p. 194 and p. 195.
G. clavifera segmentis pinnisque superioribus sub-compressis cystocarpiis in pinna infra apicem incrassata.
G. divaricata segmentis supremis (in exsiccata rugulosis) nudiusculis teretibus aut sub-compressis, cystocarpiis in pinnis cylindraceis infra apicem inmersis.
Thus it will be seen there are two differentiae given:—In G. clavifera (1) the upper segments are sub-compressed and in G. divaricata they are sub-terete or sub-compressed; now as on the same plant segments may be found showing either characteristic it is obvious that no specific character can be founded on such a small distinction, in G. clavifera the cystocarps are to be found in a thickened pinna, below the apex, but in G. divaricata they are stated to occur in a cylindrical pinna. Now in G. clavifera the young fertile ramulus is cylindrical or slightly flattened, and only becomes swollen on the development of cystocarp, so that here again we have no distinction. Fortunately, too, we have been able to see some specimens of both species collected by Berggren and named by Agardh. There is certainly no greater flattening of the ultimate pinnules in the specimens of G. clavifera than there is in those of G. divaricata. There is only one immature cystocarp on the specimens of G. divaricata, and that is of the type described (viz., immersed below the apex in a cylindrical pinna), but there can be no doubt that as it matured it would develop into the usual form of the G. clavifera cystocarps (Fig. 10). We must therefore come to the conclusion that Agardh's description of G. divaricata does not separate it from G. clavifera J. Ag. Nor is it distinct as shown by the specimens from his G. decipiens. According to Agardh G. decipiens is channelled, and this would at once separate it from his G. divaricata; but Agardh's specimens
of G. decipiens are not channelled, nor are they clearly separated by any character from such fragments of G. divaricata J. Ag. as we have seen. In fact these fragments might well be, and probably are, parts of G. decipiens J. Ag.
Now we have several hundred specimens with regular or fairly regular dichotomous branching, pinnae ramuli and clavate marginal cystocarps. These vary much in thickness of the frond, relative length of the divisions between the dichotomies, breadth and compression of the segments (sometimes being round or again flattened) obtuseness or acuteness of the terminal branchlets, width of divarication, and in other ways, at the same time it seems impossible to find distinctive characters between the various groups (Figs. 32–35). All that can be done at present is to treat them as one multiform compound species with a number of varieties. There is a tendency for certain forms to be confined to certain localities but the differences between such forms are not sufficiently determinate or uniform to enable them to be classed as distinct species. The plant is known from the Snares to Wellington, and is abundant along the East Coast of the South Island. The type locality is apparently the Bluff, for Berggren's original specimens were collected there. Specimens from the Chatham Islands collected by Mr. W. R. B. Oliver, however, exactly correspond with Agardh's Bluff specimens, which we are using as the type of our variety vera.
Gigartina clavifera J. Ag., Epicr. p. 194.
Fronds tufted regularly dichotomously divided with occasional lateral branches distichous, 5 cm. - 20 cm. long, 1 mm. - 5 mm. wide, the greatest breadths to be found chiefly in tetrasporic forms. Thickness very variable, .25 mm. - 2 mm., from cartilaginous to membranous. Branches widely divaricating, or more or less strict, terminal branchlets occasionally somewhat curved, convex above, concave below, young cystocarpic plants produce numerous crowded pinnules on the ultimate or penultimate segments of the frond. Pinnules usually simple and straight but sometimes bent, curved, or crooked or again irregularly pinnately branched, usually marginal, but occasionally from the surface of the frond, and when fully developed .5 cm. - several cm. in length. These develop clavate cystocarps occasionally secund, but more usually bilateral. Fertile ramuli usually cylindrical, or occasionally more or less flattened. Cystocarps very diverse in form and number sometimes solitary on the end of a simple ramulus, or numerous on an irregularly branched pinnule up to ten or more in number. Younger cystocarps without involucral pinnules, but in more advanced stages there are usually one or several involucral pinnules of varying length 1 mm. - 2 mm. long and irregularly placed, rising from below, or from the side of the cystocarp or above it. Tetrasporic forms are regularly dichotomous, more flattened without pinnules, much thinner at the tips, and bearing the tetraspores in scattered sori in the ultimate and penultimate branches. The following varieties may be recognized.
G. clavifera J. Ag. var. vera var. nov. Figs. 9, 10 (p. 116), 32 (Pl. 8).
Stipite saepe brevi teretique, fronde teretiuscula aut plus minus compressa, dichotome regulariter decomposita, carnoso-cartilaginea,
apicibus angustis in forma cystocarpica 1 mm. - 2 mm. in diam., segmentis 2 cm. - 4 cm. longis.
This, which is the common form in the southern part of the South Island, occurs as far north as Gore Bay. The type specimens are from the Bluff. There are usually five or six dichotomies in succession, and the plant is 10 cm. - 15 cm. long. The branches separate at an angle of from 35°–45°, remaining (in the cystocarpic forms)
Fig. 9. × 4. G. clavifera var. vera (a-f): Tips of pinnae.
Fig. 10. × 4. G. clavifera var. vera (a, b and c): Cystocarpic pinnules showing typically clavate cystocarps.
Fig. 18. × 5. G. decipiens (a and b): Cystocarpic pinnules; (c) A. hooked cystocarpic pinnule; (d) A cystocarp.
comparatively thick and coriaceous even to the ultimate segments. In the tetrasporic forms, however, the segments are as much as 5 mm. across. Cystocarpic forms throughout summer and autumn, tetrasporic plants at Akaroa in September.
G. clavifera J. Ag., var. pseudo-pistillata, var. nov. Fig. 33 (Pl. 9).
Fronde cylindracea per totam longitudinem vel levissime compressa, ramis patentibus (2mm. in diam.), pinnulis strictis crassis, segmentis longis 4 cm. - 6 cm.
This variety approaches very closely in general appearance to the European G. pistillata, a little stouter perhaps and with the branches more widely divaricating. It is, of course, quite distinct in the form of the cystocarps. It is probably one of the forms included in Harvey's collection, and identified by him with G. pistillata. Our specimens are from Monument Harbour (Campbell Island), Enderby Island (in the Auckland group), and Kekerangu on the Kaikoura coast. They doubtless approach somewhat to the Australian G. disticha as they sometimes show a tendency to pinnate branching, but see further under that species. This variety differs from var. vera in the wider dichotomies rather more cylindrical and stouter branches, and also perhaps in the longer segments between the dichotomies.
G. clavifera J. Ag. var. tortuosa var. nov. (=== G. macrocarpa Lg. 1909, p. 506) pseudo-pistillatae var. similis, angustior autem, strictior ramis 1 mm. - 1.5 mm. latis, teretiusculis, cystocarpiis in pinnulis teretibus curvatis, tortuosis, ramis strictis, .5 mm. latis. Fig. 34 (Pl. 9).
This form is very distinct from any other, and only known to us from the Snares. It might have been regarded as a distinct species as the crooked, sharply bent, or curved pinnules seem to present a character which separates it from the other forms of the genus, but certain St. Clair plants show intermediate stages between it and the more common forms, and it seems hopeless to endeavour to separate it completely. The St. Clair forms are broader and do not show so much curving and tortuosity in the pinnules, but are sufficiently like var. tortuosa to prevent us from regarding the latter as a separate species, which we were at one time inclined to do. The Snares plants were collected by Mr. J. Crosby Smith, during the Hinemoa expedition, and the St. Clair forms were also collected by him. In “The Sub-Antarctic Islands of New Zealand,” the senior author, following A. Gepp treated this as a form of G. macrocarpa, but a better knowledge of the latter species shows it to be quite distinct.
G. clavifera J. Ag., var. tenuis var. nov. Fig. 35 (Pl. 10).
Stipite sub-cuneata compressa, var. vera tenuiore, apicibus compressis, membranaceis, 3 mm. - 4 mm. in diam. A much thinner and more flattened form, almost membranaceous. The stipe is no longer cylindrical but compressed and broadening at the top, the segments are broader, and the tips much wider and compressed. Intermediate forms may be found between this and var. vera, with the cystocarps sometimes sub-secund, and the ultimate segments slightly curved. This form might possibly be regarded as a variety of G. decipiens, but apparently does not produce the flattened non-fertile pinnules so characteristic of G. decipiens. Intermediates are common at Timaru between this and G. decipiens with the terminal segments so shortened that the ultimate branches are flabellate. Wellington and Timaru. (Other forms may be met with not herein described.)
6. Gigartina flabellata J. Ag. 1851. (Species inquirenda.)
The type locality is Port Phillip. We have a specimen from Point Lonsdale collected by Mr. A. H. S. Lucas and named by him G. flabellata J. Ag. It is quite different from any New Zealand form seen by us. We have also a second specimen from Lyall Bay collected by the senior author and named by the late Major Reinbold G. flabellata J. Ag. The forms from Lyall Bay and Point Lonsdale are quite distinct. Now G. flabellata first appears as a New Zealand species in Grunow (1867) p. 70.* No note is attached to it, and consequently one cannot compare it with the description. On receiving Major Reinbold's identification the senior author inserted this species in his list 1902, p. 333. We have only one specimen of it, and as that is sterile, it is really insufficient for identification. Agardh's original description, 1851, p. 265, is as follows:—
“G. flabellata J. Ag. (1851) p. 265, fronde teretiuscula dichotomo-fastigiata, flabellata ramulisque pinnatim dispositis sub corymbosa, segmentis obtusis, cystocarpiis in pinnulis eorymborum lateralibus, soris in segmentis ultimis utrinque sub-lineariter expansis abbreviatis oppositis.”
To this description is appended a group of notes, giving some additional details. The chief distinctive character is apparently the obtuse sub-corymbose pinnules, bearing the cystocarps. In Agardh's specimens these were not well developed, and he suggests 1855, p. 265, that this may be the G. pistillata of Mont. Voy. Pole sud p. 119 from the Auckland Islands. Now as our own specimen from Lyall Bay is sterile, we cannot compare it with the description of the cystocarpic plant, and as the specimen sent by Lucas is distinct from anything we have seen in New Zealand, we are in much doubt as to whether we have G. flabellata J. Ag. here. However, the species may perhaps be allowed to stand for the present, Grunow's plant may be re-identified or good examples may later be found in New Zealand. At any rate, it seems better to insert it as a species inqwirenda, than cut it out straightway.
G. disticha Sond 1845. (Species excludenda.)
G. disticha Sond. Bot. Zeit. 1845, p. 55, from Western Australia first appears as a New Zealand species in J. Ag. (1876) Epier., p. 194, and reappears in J. Ag. 1877, p. 16 as from Dunedin collected by Berggren. It is figured by Harvey in Phycologia Australica, Plate 297. Harvey there suggests that the plant may be a form of G. pinnata or even of G. livida. Now as will be shown presently G. pinnata and G. livida are barely separable. G. livida is a plant of which we have numerous specimens, and with which Harvey's plate does not correspond. This plate shows a plant which is nearer to our G. clavifera var. pseudo-pistillata than to any other New Zealand form with which we are acquainted, but in G. disticha according to Harvey loc. cit. the cystocarps are solitary in the tips of the pinnules. He makes no mention of any involucral ramuli, and Harvey further describes the plant as pinnately decompound pinnae distichous. Agardh on the other hand, 1876, p. 194, states the plant is dichotomous, and places it in his group excipulatae, i.e., with the cystocarps
[Footnote] * It also appears in Harvey Gibson, 1893, p. 1.
girt with pinnellae. Thus as the original description of Sonder is not procurable, as the type is from a remote district, and as there are such discrepancies in the descriptions available, we consider it advisable to exclude this plant from the list of New Zealand species.
Further we have seen many specimens of Gigartina from Dunedin and its neighbourhood collected by J. Crosby Smith, W. Scarfe, and R. M. Laing, and we have none which coresponds with Harvey's diagram and description. Agardh's specimens are probably forms of the polymorphic G. clavifera, quite possibly our var. pseudopistillata, with which on the whole his description well agrees.
7. G. laciniata J. Ag. 1876.
This species is unknown to us, unless a solitary sterile specimen from Little Barrier Island, which corresponds fairly well with the description, belongs to it. It has been collected only at the Chatham Islands. The following is Agardh's description:—
G. laciniata J. Ag. Epicr. (1876), p. 197, frondibus a stipite teretiusculo complanatis sublinearibus, margine in lacinias cuneato-lineares decomposito-pinnatas laciniatasque demum densissimas undique obtegentes exuberantibus, lacinulis obtusis emarginatis crenatisve fructibus. … Divsionis norma cum G. Wehliae convenit, at multa minor et angustior et demum ita decomposita ut lacimiis undique obtegentibus rachides haud conspiciantur.
Hab. ad insulas Chatham.
8. G. livida (Turn.) J. Ag., 1851. Figs. 11 (p. 110), 12 (p. 108), 36 (Pl. 10).
This is one of the first species of seaweed to be described from New Zealand. It was given to Dawson Turner by Mr. Menzies surgeon to Vancouver's expedition, who, in 1791, collected in Dusky Sound, and doubtless it was there that the original specimens were collected. However, Turner's description merely notes, “In the Southern Ocean, Mr. Menzies.” The plant was described by Turner in 1819, vol. 4, Historia fucorum, p. 140, and his illustration is sufficiently good to enable the plant indicated to be readily identified. The senior author has collected in Dusky Sound specimens which exactly corespond with those of Turner. In (1851) p. 270, J. Ag. described a species G. pinnata. He separated this from G. livida because of its more flattened frond. According to Agardh (loc. cit.) the frond of G. livida is sub-canaliculate and that of G. pinnata quite flat. However, many of the narrower, cartilaginous Gigartinas become channelled or rugose on drying though they may be cylindrical or flat when fresh. This character can only be of value when it occurs in growing plants, as in G. canaliculata. Now G. livida is normally flat, and any channelling that does occur is subsequent to drying. The original specimens collected by Menzies were apparently small and narrow, whereas G. pinnata is usually represented as a much broader and larger plant. However, we have a specimen of
undoubted G. livida from Dusky Sound, which quite equals in size and breadth the ordinary forms of G. pinnata, though it is probably the case that G. livida as it occurs on the Tasmanian and Australian coasts is better developed and larger than the usual form of Southern New Zealand, but we can find no other differences. It would perhaps, however, be unwise as yet definitely to assimilate them, because of their different habitats.
Further Agardh himself later recognized the close similarity of the two species, 1899, p. 11, footnote 2: “species a me nomine G. pinnatae et G. lividae olim distinctas, vix nisi formas sistere ejusdem speciei mihi magis magisque persuasum, habui. Specimina revera obvenire alia magis obvenire magis elongata et tota quasi pinnatim decomposita, alia breviora, quarum pinnas principales dichotomas quasi appendicibus brevioribus obsitas vidi, at tot transitus inter extremas formas vidi ut ejusmodi diferentiis hodie haud insistere auderem.”
As a result of this note the senior author (1926), p. 151, No. 187, identified G. livida with the Australian G. pinnata. Unfortunately our specimens of the species, most of which have been kept in formalin for a long time, are in a poor state of preservation, but we have both tetrasporic specimens and young cystocarpic plants. The tetrasporic plants—unlike those of some other species—are the same in form as the cystocarpic.
Gigartina livida (Turn.) J. Ag. Sp. II., p. 270.
Fronds tufted, dark red to brown but tending to fade to dull livid yellow purple, at first in the young plant dichotomously branched but soon becoming more or less regularly pinnate, in New Zealand specimens 4 cm. - 10 cm. long, but in the Australian and Tasmanian G. pinnata sometimes apparently much larger. Main stem below the branches of varying length but usually short linear, subcuneate. Primary pinnae opposite, alternate, or irregularly placed, occasionally two or three in succession on one side, broadest in middle and tapering to both ends, up to 8 cm. or 10 cm. in length and 5 mm. to 7 mm. wide, beset with the secondary pinnae, 1 cm. - 2 cm. long, 2 mm. - 3 mm. broad, and similar in shape to the primary pinnae, distance between the secondary pinnae 2 mm. - 5 mm. They again bear the pinnules which are often mere lobes 2 mm. - 3 mm. in length, but sometimes are 1 cm. in length. In fertile specimens the tertiary pinnules bear behind the apex one or several irregularly pinnulated cystocarps (Fig. 12). Tetrasporic fronds similar bearing numerous tetraspores scattered throughout the whole frond. Substance of the frond cartilaginous, but more flattened and not so thick as in G. angulata which it sometimes approaches.
Perseverance Harbour (Campbell Island) J. C. Smith! Dusky Sound, Deas Cove (Doubtful Sound), Riverton, Akaroa, Brighton (Otago), Keri-Keri (Auckland), and The Chathams, R.M.L., Jackson's Bay, Lyall! Black Head, The Cave and Seal Rock (Dunedin), W. A. Scarfe!
Rabenhorst 1878 records G. pinnata, p. 70, J. Ag. from the Aucklands, and it is also thence recorded by Grunow 1867, p. 70, Grunow remarking that it is almost certainly the same as G. livida.
Perhaps the most characteristic feature of this group is that cystocarpic pinnules are at times produced from the surface of the lamina. According to Agardh's classification it contains three New Zealand species.
9. G. protea J. Ag.
10. G. marginifera J. Ag.
11. G. polyglotta J. Ag.
However, we propose to add a fourth species to the list.
12. G. decipiens Hook. f. et Harv.
The last-named species is placed by Agardh in his group canaliculatae; and was also placed by Harvey within his division, “frond thick, channelled.” Now G. decipiens Hook. f. et Harv.—if we have rightly identified it, and we have little doubt about it—is not normally channelled. Harvey had only seen dried specimens, and these sometimes have the margins of the frond incurved, when the lamina has numerous cystocarps upon it. On the one hand G. decipiens Hook. f. et Harv. intergrades with G. clavifera, and on the other with G. protea from which in some of its forms it is scarcely specifically distinct. It should therefore be undoubtedly placed with G. protea. Reference may be made to a fifth species, placed by Agardh in this group, but not hitherto recorded from New Zealand, G. volans J. Ag. This is a doubtful form, which in any case belongs to the radula group, and may be left out of consideration here, though we have in New Zealand plants which correspond fairly well with it.
9. Gigartina protea J. Ag. 1885. Figs. 13 (p. 110), 14 (p. 108), 37, 38 (Pl. 11).
G. protea was described by J. Agardh in 1885 from specimens from the West Coast of New Zealand. He considers it to be intermediate between G. decipiens J. Ag. and G. marginifera J. Ag. and to be separated from the latter by the more dichotomously decompound sterile lower portion of the frond. However, there are other differences. G. marginifera is larger and much narrower in the segments, and when fresh is olive green in the upper part of the frond, red below, whereas G. protea is, though olive green above, almost black below when fresh, and goes black throughout on drying.
The two species are quite distinct and other differences will appear in the course of the description of each. G. protea is best known to us from Lyttelton specimens. There it is abundant on rocks exposed to the North-East swell on the reclamation works beyond the Gladstone pier. Other specimens come from Timaru and Wellington, but scarcely match completely the Lyttelton ones, which have been chiefly used in the course of description. As Agardh only gives the habitat of his specimens as the West Coast of New Zealand, we do not know the type locality. However, though both he and Dr. Cotton have determined Lyttelton specimens, collected by the senior author, as G. protea, somewhat doubtfully it is true, there can be little question that these forms are fairly typical of the species. Though not so protean in form as G. clavifera it does show a certain amount of polymorphy, and occasionally, as has already been noted, intermediates between the two species may be found. As G. clavifera
has not been found at Lyttelton, hybrids cannot be expected, and specimens of G. protea are here almost uniform. At Lyall Bay where both species occur there is much variety in the forms to be obtained. There is no single uniform character separating G. protea from G. decipiens Hook. f. et Harv., and it is possible the former may be only an epharmonic form of the latter, but this point will be discussed more fully under G. decipiens.
G. protea J. Ag. Bidr. Alg. Syst. 4, p. 29.
Densely tufted each frond is usually 5 cm. - 10 cm. in length (in tetrasporic plants 15 cm.), cylindrical only at the base itself and becoming flattened at once into a sub-cuneate stipe which branches dichotomously. This branching is repeated two or three times only. Occasionally by the reduction of the intervening segments three or four branches arise at one point, at other times an adventitious lateral branch may appear. The segments vary in width from 3 mm. - 10 mm. and in the case of tetrasporic plants they may be broader still (1.5 cm.). (An unusually large cystocarpic plant from Timaru, doubtfully belonging to this species, is 20 cm. long, with a maximum breadth of segment of 1.2 cm. and has as many as six dichotomies in succession, the frond becoming thin and membranous towards the tips). The frond is usually thick and coriaceous. Young cystocarpic fronds are densely pinnated from the margins with somewhat flattened pinnules up to 1 cm. in length, slightly lingulate, usually simple but becoming irregularly branched as they grow older. Numerous papillae also arise from the surface of the frond (Fig. 13), usually chiefly on one side and develop into similar cystocarpic ramuli. In luxuriant specimens the lamina becomes channelled and completely covered with these ramuli. They are most abundant between the second and third dichotomies, and absent from the base of the frond, and sometimes from the tips. The clavate cystocarps are similar to those of G. clavifera. Tetrasporic specimens (Lyttelton, Nov.) are broader and longer (Fig. 37d) and have sori abundantly and irregularly scattered throughout the upper half of the frond and are often pinnate (Fig. 38). Cystocarpic specimens may be found from September to May, and possibly all the year round, though the plant is apparently annual.
Timaru, Lyttelton, Wellington, R.M.L. Akaroa (in 8 fathoms), H. Suter!
10. G. marginifera J. Ag. 1876. Figs. 15 (p. 110), 16 (p. 108), 39 (Pl. 12).
This is in its normal form a very distinct species, passing however on one side into G. clavifera and on the other into G. angulata and G. livida, Agardh describes the branching as pinnate-decompound. We have seen specimens collected by Berggren at the Bay of Islands and named by Agardh, which might be so described. The majority of our specimens come from Gore Bay, and show both dichotomous and pinnate branching, with a preponderance of dichotomous forms. The cystocarpic form was not seen by Agardh, we however collected it at Gore Bay in November and April. When collected, the plant is frequently a dark olive-green in this respect resembling G. Chauvinii, but it usually dries to a dark brown-red or purple. It is perhaps not so polymorphic as G. clavifera, but as with many other
species it is comparatively easy to describe the plant from a few more or less uniform specimens from one locality, but it becomes more and more difficult, the wider the collecting area examined, and the greater the number of specimens collected. Dried specimens of G. marginifera are usually readily recognized by the broadening upwards of the terminal segments, and by the reddish or purple character of the upper portion of the frond, but these are not constant characters.
G. marginifera J. Ag. Epicr. Florid., pp. 196 and 683.
Tufted and variously branched, 10 cm. - 20 cm. long, with narrow flattened linear stipe, several cms. in length, gradually broadening to the first branch, usually dichotomously, but sometimes pinnately or partly pinnately and partly dichotomously branched, segments long or short, in the latter case the frond becomes flabellate, ultimate segments oblong to linear oblong, up to 10 mm. in diam. usually broadening upwards truncate and notched at the tips, but sometimes narrowed to the tips and obtuse or even acute. The margins fringed with numerous pinnules varying very much in form and appearance with the age and state of the frond, in their earliest stages 1 mm. - 2 mm. long. Cylindrical but soon becoming flattened, spathulate, lingulate, and ovate, 10 mm. - 15 mm. in length, finally branching irregularly. During their development the surface of the frond becomes papillose, and similar ramuli are developed on it, ultimately the frond becomes rugose and channelled and in this stage narrow forms of the plant are very similar to G. angulata. Cystocarps developed behind the tips of pinnules most varied in form, densely aggregated or solitary, tubercled, rarely with a solitary more or less terminal pinnule, sometimes developed in dense masses on the irregularly branched ramuli so as to cover the whole surface of the frond. Tetrasporic form similar with fewer pinnules and ramuli, sori scattered through the frond but absent from the tips of the segments and pinnules.
The Bluff, Double Corner (Amberley), Gore Bay, Lyall Bay, R.M.L. Bay of Islands (Berggren!)
Tetrasporic plants (Gore Bay, Nov.). Cystocarpic (Gore Bay, summer and autumn).
11. G. polyglotta J. Ag. 1885.
We have no specimens which we can definitely assign to this species. According to Agardh 1885, p. 29, it is nearest to G. protea, but apparently differs in the thinner frond, acuminate apices, and in the principal segments being narrowed to both ends. Agardh's specimens came from the western shores of New Zealand. We reproduce Agardh's description for the sake of completeness.
G. polyglotta J. Ag. Bidr. Alg. Syst. 4, p. 29.
Fronde tenuiore, submembranacea, plana lineari decomposito-dichotoma apicibus acuminatis, segmentis principalibus basi apiceque attenuatis, sublanceolato-linearibus decompositis, superioribus a latiore basi sursum attenuatis, omnibus demum ramentis lingulatis utrinque acuminatis a margine pinnatis, disco sparsim novis emergentibus rudi, cystocarpiis in pinna transformata provenientibus, infra apicem parum productum, corona loborum excipulatis.
G. polyglotta is probably only a form of G. protea or the more protean G. dicipiens, and is scarcely likely to maintain its specific rank. There is really nothing to distinguish it but the acuminate apices and pinnules, a character which varies much in other species of the group.
12. Gigartina decipiens Hook. f. et Harv. 1845. Figs. 17 (p. 111), 18 (p. 116), 40 (Pl. 12), 41, 42 (Pl. 13), 43 (Pl. 14).
The plant was originally described under the name Iridaea decipiens Hook. f. et Harv. in the London Journal of Botany, 1845, p. 547. This publication though at one time in the Reference Department of the Public Library, Christchurch, is not now obtainable in New Zealand, so we have had to depend in the first place for identification upon the description of the plant in Hooker's Handbook of the New Zealand Flora, vol. II, p. 700. Kuetz, 1849, p. 729; and J. Ag. 1851, p. 257 are merely reproductions of Harvey's original description. The plant was originally collected by Raoul, and therefore was probably obtained first at Akaroa, for it apears to be chiefly a South Island form. Harv. 1855, p. 252, lists the plant under the name Gigartina decipiens, but provides no description or further information. J. Ag. 1876, p. 195, provides a fresh description, but appends a note from which we quote, “specimen Harveyanae plantae non vidi, at specimen ad oras N. Zelandiae frequentiorem, in descriptionem datam bene congruentem Harveyanam judicavi,” and in 1877, p. 16 gives as habitats, Dunedin, Banks Peninsula, Berggren. Now we have seen specimens of G. decipiens of J. Ag. collected by Berggren at Banks Peninsula, and were at first inclined to regard it as different from G. decipiens Hook. f. et Harv. We have also seen a drawing of one of Harvey's original specimens in the British Museum, and though if we had only these specimens to go upon we would certainly have regarded them as different species, after examining scores of specimens from the East Coast of the South Island, it becomes more and more difficult to find any permanent distinctive characteristics between the three species G. decipiens, G. clavifera and G. protea. We have unfortunately seen no type specimens of any one of the three species, but we have seen specimens of all three as identified by Agardh. What we take to be the normal form of G. protea is (or was) to be found in great abundance on exposed rocks near the rubbish dump at Lyttelton. Of G. decipiens characteristic specimens are common at Moeraki, Dunedin, and Timaru, and of G. clavifera var. vera from the Bluff northward along the east coast of Otago. At Timaru there is an immense mixture of forms, in which G. decipiens var. semi-palmata (Plate 17), is perhaps most abundant, but G. protea and some forms of G. clavifera also occur. It seems, however, better to retain the species as described without any attempt to sort out such jordanons or hybrids as may be present, and to recognize that we have here one or more compound species which require much further investigation before a complete and satisfactory classification can be made.
Gigartina decipiens Hook. f. et Harv. Lond. Journ. of Bot. 1845, p. 547.
Densely tufted, frond when fresh almost black fading to a dull brown at the tips, when dried usually a dead black, sometimes
slightly channelled. In some thinner tetrasporic plants the terminal segments when dried are almost bright red, usually five to seven times regularly dichotomously branched with occasional adventitious lateral branches, more or less flabellate. Stipe 1 cm. - 4 cm. long sub-cuneate, average length 10 cm. - 15 cm., but specimens 20 cm. - 25 cm. long may sometimes be met with. Breadth of segments very variable, perhaps averaging before division 5 mm. - 7 mm., but specimens may be met with in which they are 10 mm. - 15 mm. or more. Tips usually obtuse or truncate before division, but occasionally pinnulate and acute or acuminate. Fertile ramuli cylindrical or flattened, simple or most variously branched and most varied in arrangement, sometimes placed regularly along the margins of the frond equidistant, numerous and simple, sometimes covering the disc as well, at other times densely aggregated and copiously and irregularly branched in certain regions of the frond, bi- or tripinnate or dichotomous whilst the rest of the frond is more or less naked. Non-fertile pinnules abundant, linear to linear lanceolate thin and flat (Fig. 17b). The stipe as in other species is always without pinnules, whilst the tips may or may not be pinnulated (Fig. 17a). Probably most of the pinnules remain sterile and disappear, for cystocarps are usually compartively sparsely developed. Cystocarps clavate as in G. clavifera (Fig. 18). The tetrasporic plants are usually thinner, broader, not so frequently branched, without pinnules, and carry scattered sori irregularly scattered throughout the frond. (Fig. 42, Pl. 13).
G. decipiens J. Ag. var. semi-palmata var. nov. Fig. 17c (p. 111), 43 (Pl. 14).
Apicibus, compressis, flabellatis, lingulatis vel spathulatis.
The above variety appears to be distinct, and is very abundant at Timaru, where during most seasons of the year it forms a fringe round the outer side of the North Mole with G. angulata and other forms of G. decipiens at low water mark. Owing to the shortening of the sub-terminal segments 3 - 5 of the flattened terminal apical branches spring approximately from the same point (Fig. 17c). The whole plant is perhaps thinner than other forms of decipiens. Dunedin, Timaru, Double Corner (Amberley).
As already pointed out it is practically impossible to give determinate characters separating all forms of G. decipiens from G. clavifera and G. protea, still some attempt should be made to point out the most characteristic points of identification. In many cases, however, an individual specimen can only be determined when judged by the company it keeps. Usually, of course, G. clavifera has few if any cystocarps on the lamina of the frond, its segments are long and narrow, and it does not produce the tangled masses of branched pinnules not infrequently to be met with in G. decipiens. Again G. decipiens is usually much broader than G. clavifera, and never terete or subterete as the latter often is. The specimens of G. decipiens identified by J. Agardh that we have seen are seven in number and only two of them alike, one is densely flabellately branched, another is sparingly dichotomous, a third is covered with flattened non-fertile linear pinnules (1 mm. - 1.5 mm. broad), and it is this last point and the broader more subcuneate segments which perhaps best separates them from most forms of G. clavifera in which these non-fertile
pinnules are usually absent. G. clavifera has also segments narrower and usually of more uniform breadth. G. protea is stouter than G. decipiens, thicker and in spite of its name so far as we know it more constant in form. In G. decipiens there are often as many as six dichotomies in succession, in G. protea rarely more than two or three. We have however one specimen of G. protea (?) from Timaru with six dichotomies and thin flattened tips. G. protea so far as we have seen is never channelled, but specimens of G. decipiens, particularly if dry, are often somewhat channelled on one side. Forms of G. decipiens approaching G. protea are often to be distinguished by this character. Between G. protea and G. decipiens on the one hand, and G. clavifera on the other, the main distinction of course is that the first almost always, the second commonly, and the last rarely, bears fertile ramuli on the surface of the lamina. A word of caution should perhaps be added about certain non-fertile, non-pinnulate, regularly dichotomous forms of G. decipiens found at Timaru and elsewhere. These are scarcely to be distinguished from similar forms of G. clavifera, also in the juvenile state, but usually the accompanying fertile pinnulated forms will show which species one is dealing with, but it is to be admitted that from a fragment it is often quite impossible to decide which species is before us.
(This tribe is so named to distinguish it from the following one armatae not occurring in New Zealand, in which the frond is armed with points and hooks. It is distinguished by its pinnately distichous branching from Tribe 3 prolificantes, and the cystocarps arising from the surface of the lamina separate it from the first two tribes of this division.)
13. Gigartina chauvinii (Bory) J. Ag. Fig. 19 (p. 108), 44 (Pl. 14).
This species was not admitted into the senior author's list, as there appeared to be insufficient evidence for its occurrence in New Zealand. J. Ag. (1876), p. 193, gives as habitats the western coast of South America and New Zealand, but it does not appear in the list of New Zealand seaweeds (J. Ag. 1877). Presumably therefore he then excluded it from his list of New Zealand species. However, Miss M. Crookes has sent us specimens from Muriwai (Auckland) which quite evidently belong to this species, and it must therefore be now definitely included in the New Zealand list. There are two other species closely allied to this and probably not distinct, G. Lessonii (Bory) J. Ag., and G. Chamissoi (C. Ag.) J. Ag. Howe 1914, pp. 99–103, still retains the three species, though he says (loc. cit.) p. 100, “However Gigartina Chauvinni and G. Lessonii … appear to be connected with the earlier described G. Chamissoi by a full series of intermediates,” and again under G. Chauvinii, p. 102:—“The narrower forms (i.e., of G. Chauvinii) appear to intergrade hopelessly with G. Lessonii.” We have specimens agreeing almost exactly with that photographed by Howe 1914, Plate 38, as G. Chauvinii, though ours are perhaps somewhat smaller with shorter pinnae. We therefore retain the name G. Chauvinii. The plant has been obtained by a number of collectors from Peru to Cape Horn, and is only known elsewhere from New Zealand. It is green in colour when fresh, but
dries to black. In Peru it is used as an ingredient in salads, soups and fritters, and sold in the market under the name Uyos. G. Lessonii is usually dichotomously branched, with the main axes nearly terete. G. Lessonii has the frond compressed and linear, and irregularly sparsely pinnate. Some of our specimens seem to approach to this description, but we have none to correspond with G. Lessonii as figured by Howe (loc. cit.) plate 37, and we have seen no South American specimens of any of the forms. The original record of G. Chauvinii from New Zealand is to be found in Mont. Voy. Bon., p. 72. A copy of this work is not available to us here.
G. Chauvinii (Bory) J. Ag.
Frond up to 25 cm. or more in length, stipe narrow and flattened at the base but gradually expanding to a breadth of 5 mm. - 8 mm., lamina 10 mm. - 12 mm. in breadth linear oblong, bearing numerous pinnae on each side several cm. in length and several mm. in width. These are sometimes again pinnate, but there is considerable variation in length and width of frond. Numerous cystocarps more or less globose, clavate or tubercled are borne on the margins of the pinnules (Fig. 19 b, c, and d), or in irregularly branched ramuli which spring in masses from the surface of the frond. The tetrasporic frond (Fig. 44a) (without the irregularly branched ramuli) bears numerous sori irregularly scattered throughout the main lamina and pinnae. Both forms of fructification are absent from the tips and bases of the fronds.
Muriwai, M. W. Crookes!; Waipu Cove, R.M.L. Brcaker Bay, (Cooks St.), W. R. B. Oliver!; Lyall Bay, W. A. Scarfe!
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.
18. Gigartina tuberculosa (Hook. f. et Harv.) Grunow 1867. Fig. 26 (p. 128).
Hook. f. et Harv. (1844–47) i., p. 188, described from the Auckland Islands a seaweed Chondrus tuberculosus, this was afterwards (1867), p. 70, placed by Grunow in the genus Gigartina, in which it has since remained. Agardh does not seem to have seen specimens of it for it is placed by him (1876), p. 179, in his species inquirendae. The plant is known from the Auckland Islands and from the West Coast of South America, from Peru southward to Cape Horn. It is apparently closely related also to the South African G. fastigiata J. Ag., of which however the cystocarps are unknown, and which does not appear in Agardh's final list 1899, p. 9 et seq. According to Howe 1914, pp. 105–106, “the Peruvian plant differs somewhat from the New Zealand originals preserved in the Royal Botanic Gardens at Kew, though the difference is less than is generally conceded to occur in related species, such as Chondrus crispus.” However this need not concern us at present, as the Auckland Island plant is the original of the species. Further, accoring to Howe loc. cit., p. 107, G. fastigiata “resembles the New Zealand plant more than the Peruvian, but its segments are only about half as broad as those of the former.” From these quotations it would appear that G. tuberculosa may be a plant of wide distribution, but in New Zealand it is only so far known from the Auckland Islands. If widely distributed elsewhere in warmer waters, its apparent absence from the mainland of New Zealand is noteworthy. According to Howe loc. cit., p. 106, it is a matter of taste rather than of structural characters whether it be
referred to the genus Gigartina or Chondrus. “The cystocarps are often sessile upon the main segments or semi-immersed as in typical Chondrus, yet in New Zealand specimens at least they are sometimes so protuberant, and carry so much vegetative tissue with them that they may be said to occupy reduced ramuli as in Gigartina.” Now the half-immersed cystocarps is not the only character separating Chondrus from Gigartina. According to Schmitz and Hauptfleisch (Engler und Prantl 1897, p. 354) in Chondrus, the nucleus (“fruchtkern”) is without a filamentous sheath, in Gigartina the sheath is present. If this character be recognised as definitive then our species will have to be placed in the genus Gigartina, for the carpospores are here closely surrounded by a network of sterile filaments. Further in our specimens the cystocarps are not half immersed, but completely protuberant. We have therefore decided to retain the species in the genus Gigartina, where it was placed by Grunow.
Our specimens are from the Auckland Islands, where they were collected by the senior author, during the Hinemoa expedition of 1907.
Gigartina tuberculosa (Hook. f. et Harv.) Grunow.
Fronds tufted 4 cm. - 6 cm. high, dichotomously branched, but sometimes bearing adventitious lateral branches irregularly placed. Segments 3 mm. - 5 mm. broad cuneate, gradually broadening upwards from the narrow base and concave towards the tips. There are usually 3–5 dichotomies, tips flabellate and if cystocarpic incurved towards the cystocarps, which are protuberant, numerous, wholly external and irregularly arranged below the apices on surface of the lamina, about 1 mm. in diameter, globose to discoid (Fig. 26a). Tetrasporic plants not seen.
Auckland Islands. R.M.L. (J.D.H.).
Our plants are few in number and only in a moderate state of preservation, and so it seems unwise to enter into greater detail of description that a fuller range of specimens might show to be inaccurate. According to Howe loc. cit., p. 106, “The Peruvian plant is a little less flattened and is more fastigiate in its branching, its somewhat narrower segments are less closely and less patently flabellate, dichotomous towards the apices, and its substance is rather more corneous when dry.” As Dr. Howe has compared the Peruvian plant with “The New Zealand originals, preserved in the Royal Botanic Gardens at Kew,” there can be no doubt as to the identity of the two forms. We have not seen any cystocarps so protuberant that they would be said to be on reduced ramuli. The structure of the stem is that of a typical Gigartina, the inner tissue consisting of a network of anastomosing filaments, passing out into a radial tissue of moniliform cells.
The above descriptions deal only with the species of Gigartina previously described, and do not include various new species from different parts of the coast in our possession. These must be left for subsequent discussion, and in some cases at least for the collection of further material. It is obvious from the work already done that an examination of the specimens raises in an acute form the question
of the significance of the term species. On one occasion* the late Baron von Muller proposed the amalgamation of over fifteen species of Veronica (Hebe) into one species, and one is tempted to do the same with G. decipiens,G. clavifera, G. protea, G. polyglotta, and perhaps G. chauvinii. They are so multiform that it is often impossible to separate them, yet one must admit that behind this great assemblage of forms there are probably several jordanous. However, one would have to live on the sea-shore for some years, and be able to segregate different forms, in order to ascertain definitely if this were the case. At present it is only possible with a long series of specimens to group plants round a central type, and endeavour to unite them under broad definitions. Further examination of the coasts is required. Only the forms on the East Coast of the South Island have been extensively collected, and even here much further search is required at different seasons.
The large foliose forms of the G. radula type also present similar difficulties. It is hoped to deal with these species in a subsequent paper, but it is obvious that no analysis of the characters can result in clear-cut results. Probably these can only be obtained by growing the plants at Experimental Stations.
We have to thank Dr. A. D. Cotton, of Kew, for assistance in the identification of some species and for comparing them with named specimens in the herbarium. This has been of very considerable assistance to us, as New Zealand Museums and herbaria contain very few specimens of seaweeds, collected by earlier investigators.
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——, J. G., 1876. Epicrisis Systematis Floridearum.
——, J. G., 1877. De Algis Novae Zelandiae Marinis.
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——, J. G., 1899. Analecta Algologica Continuatio 5.
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——, J. D., and Harvey, W. H., 1853–1855. Flora Novae Zelandiae, vols. 1–2.
——, J. D., and Harvey, W. H., 1867. Handbook of the New Zealand Flora.
Howe, Marshall A., 1914. The Marine Algae of Peru (Torrey Botanical Club., vol. XX).
Laing, R. M., 1909. The Marine Algae of the Sub-Antarctic Islands of N.Z. (in Chilton: The Sub-Antarctic Islands of N.Z., vol. 2, pp. 503–527).
——, R. M., 1926. A Reference List of New Zealand Marine Algae. (Trans. N.Z.I., vol. 57, p. 126).
Montagne, C., 1827–1840. Plants cellulaires du Voyage au Pole sud sur les Corvettes l'Astrolabe et la Zélée.
Rabenhorst, L., 1878. Beitrag zur Meeresalgenflora von Auckland Inseln.
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[Footnote] * Vegetation of the Chatham Islands, p. 45.