New Zealand Bangiales (Bangia, Porphyra, Erythrotrichia and (?) Brythrocladia). By Robt. M. Laing, M.A., B.Sc., F.N.Z. Inst. [Read before the Philosophical Institute of Canterbury, 7th. December, 1927; received by Editor, 9th December, 1927; issued separately, May 10th, 1928] Plates 1-15. Classification of the Bangiales. The order Bangiales is divided into three families (Rosenvinge 1909, p. 56), (1) the Bangiaceae, gonidia arising by division (or also without division from a mother cell, originally vegetative, (2) Erythrotrichiaceae, gonidia derived from special monospores, separated by an incurved wall from a vegetative cell, (3) Goniotrichiaceae, gonidia formed without a cell division. We are concerned at present with the first two families only, which are thus subdivided into genera (certain non-local genera are omitted). (1) Bangiaceae. Frond filiform … … … Bangia Frond flattened … … … Porphyra (2) Erythrotrichiaceae. 1 Frond erect filiform … … Erythrotrichia 2 Frond consisting of creeping branched filaments more or less confluent to a monostromatic disc … … … Erythrocladia The following species are described for New Zealand:— Bangia fusco-purpurea (Dillw.) Lyngbye. A new record for New Zealand. Porphyra columbina Mont. P. nobilis J. Ag. is reduced to a synonym of this species. Porphyra subtumens (J. Ag.) Lg. This species formerly represented by a women nudum is now described for the first time.
P. umbilicalis (L) J. Ag. var. Novae Zelandiae Lg. var. nov. To replace, P. vulgaris, P. laciniata, and P. perforata, previously described from New Zealand. Erythrocladia (?) insignia Lg. (sp. nov.) Erythrotrichia ciliaris (?) (Carm.) Batters. A species of questionable identity. Bangiaceae. Frond filiform … … Bangia. Introductory and Historical. Two species of Bangia (B. ciliaris Carm. and B. lanuginosa. Hook. f. et Harv. 1855 ii. 264) are described for New Zealand in Hooker (1867) p. 716. Bangia ciliaris is now Erythrotrichia ciliaris (Carm.) Batters; and will be further considered under that genus. B. lanuginosa Hook. f. et Harv. (1855) ii. p. 264 has not again been identified and the original description is so meagre that it is not likely I think to be rediscovered. It is probably indeed merely a young form of the species B. fusco-purpurea (Dillw.) Lyngb. now to be recorded for the first time from New Zealand. B. lanuginosa is described from specimens collected by Colenso as “parasitic on Chordaria,” no locality is given, but it would probably be the east coast of the North Island where most of Colenso's species were obtained. Bangia fusco-purpurea (Dillw.) Lyngb. (1819) Hydrophyt. Dan. p. 83. In its fresh water form this species is known as B. atropurpurea C. Ag. J. Ag. (1882) p. 36 treats B. fusco-purpurea as a variety of B. atropurpurea. I quote his description for the benefit of New Zealand students. B. atropurpurea, purpureo-violacea elongata, stratum effusum in rupibus et lignis efficiens, filis junioribus cylindraceis rectiusculis, singulis, conspicue articulatis adultioribus incrassatis curvatis areolatis, articulis in cellulas quarternas pluresque, demum numerosas et fere sine ordine conspicuo juxta-positas divisis, endo-chromatibus in filo adultiore densius farctis, spatiis intercedentibus hyalinis angustis vix conspicuis. var. B. fusco-purpurea saepe valida, marina colore dilutius aut obseurius purpurascente. There are a number of forms of B. fusco-purpurea and several closely allied species; however, I do not intend at present to discuss details, but merely to record this widely distributed aggregate species from New Zealand waters. It is known from the North Atlantic, Mediterranean, Californian, and Tasmanian coasts. Localities: On a drifted log between tide marks, Homewood, Pelorus Sound (Sept.); on the pier New Brighton, near high-tide mark (June), Dunedin, and elsewhere. Frond filiform … … Porphyra. Introduction. Amongst the seaweeds of commercial importance the genus Porphyra occupies a high position. Species of this genus are widely
used as a food, as a medicine, as a delicacy. In Japan they are cultivated, in Great Britain under the name of Purple Laver or Sloke they are regularly sold, as also under different names in Japan, Hawaii and California. It is therefore a matter of some importance, commercial as well as scientific, to ascertain the actual species existing in New Zealand. This is not easy, mainly owing to the fact that some of the earliest investigators, after a cursory examination, frequently assimilated species occurring in New Zealand with distinct European species; and it is now almost impossible to determine, without access to the original specimens, what were the New Zealand species appearing under European names. It is not proposed hereto undertake a complete investigation of the New Zealand forms; but merely to examine thorn with sufficient care and detail to enable them to be assigned definitely to their proper positions. The first difficulty that the investigator meets is the absence of any general agreement amongst algologists as to the exact systematic position of the family or group. That need not detain us long here, as it will be sufficient for our purposes, if it is clear that we are dealing with plants usually placed in the group. By older writers it was usually placed among the Ulvaceae, where it still appears in J. Agardh (1882) p. 38. However, Le Jolis (1864) p. 99 following Thuret had already placed it before the Florideae; and in this position it is usually now to be found, in the group Bangiales, accompanied by various other genera. Oltmanns (1922) Band 11 s. 230 places the Bangiales outside the Rhodophyceae, but just prior to them. (The name Phaeophyceae in Oltmanns occurring at the top of the page, is doubtless there as the result of an oversight). It has to be admitted, that Porphyra with its purple endochdrome, carpospores endowed with amoeboid motion, and intercalary growth is very different from any true Floridean; but until a better place can be found for the group, it must remain here. The absence of protoplasmic inter-cellular strands is another feature distinguishing the Bangiales from the true Rhodophyceae. It is now our purpose merely to describe in some detail the species hitherto assigned (rightly or wrongly) to the genus Porphyra, and occurring in New Zealand waters. The genus is widely distributed in all temperate and colder seas. In 1897, Engler and Prantl p. 312, recognised only 20 species, and considered the genus to be cosmopolitan; but since then many fresh species have been described, and the older species have been better delimited, so that now there are probably at least fifty recognized species, and it appears that some which were at one time thought to be cosmopolitan have a much narrower area of distribution than was previously believed. The species are often difficult to discriminate without close examination. Hence much confusion has arisen with regard to them; and this as will presently be seen has been the case especially with our Now Zealand forms related to P. umbilicalis. Apparently there are tropical areas from which the genus is absent; and the type species P. umbilicalis (L) J. Ag. at one time thought to be found in all seas, was later, after closer examination, regarded as confined to the North Atlantic. Still further examination has again extended its range to the extra-tropical seas of both hemispheres,
North Atlantic, North Pacific, Cape of Good Hope, South American, Sub-Antarctic, etc. I now propose to regard the New Zealand plant as a variety of this nearly cosmopolitan species. Earlier investigators were content to describe the species of this genus in terms of colour, consistency, shape, and general appearance. Hence the original belief in their cosmopolitan nature. But later investigators showed that these characters were subject to so much modification, dependent on ecological conditions and the treatment of specimens, that they were for the most part unreliable for the discrimination of species. Subsequently during re-examination the tendency was to limit specific areas, and these again are now tending-to be widened with the increase of more definite knowledge. Thus it again appears to be probable that P. umbilicalis (L) J. Ag. is an almost cosmopolitan plant; and probably in all its forms valuable for food. Engler and Prantl (1897) p. 308 give as one of the chief marks of the Bangiales a single star-shaped chromatophore with a central pyrenoid. In most of the New Zealand forms the pyrenoid is with proper treatment quite readily visible; but it is by no means evident that the chromatophore is always star-shaped. Usually the single chromatophore fills the whole lumen of the cell, though at other times with different treatment it shows an irregular margin. In Porphyra subtumens it is somtimes granular in appearance; but it has not yet been dearly ascertained that the granules are discrete, and so the species has, for the present at any rate, been left within the genus. No attempt has been made in this investigation to make a detailed or cytological study of the cell contents, consequently they will not be further dealt with here. It is usually considered that the chromatophore contains both phycoerythrin and phycocyan, thus giving to Porphyra its purplish colour. But this colour varies much with the age, state, and environment of the specimen. New Zealand forms in the fresh state are often of a dark translucent sherry-colour when viewed by transmitted light; but a brown, black as they hang glistening from the tidal rocks. The colour changes when the plant is dried and preserved in a herbarium, and goes through a large number of more or less indefinable shades, tan, purplish, wine-red, plum-colour; and it is unfortunately chiefly from herbarium specimens that the colour has been described. In some cases after the plants have been dried for a time, the colour is sufficiently determinate to be of value for diagnostic purposes; but it must always be used with caution for this end. Similarly in respect to the form. This, though to some extent characteristic, varies with the age, habitat, and other circumstances of the plant, and is in itself insufficient to determine the species. History. (A) The first species known from New Zealand was P. columbina Mont, from the Auckland Islands. (Montagne in D'Uville 1845, p. 33). There can be little doubt that this is the common Porphyra throughout New Zealand and the adjacent islands.
(B) Harvey in Hooker 1867, p. 715 following on his work in the Flora Novae Zelandiae, and the Flora Antarctica, lists three species. 1 P. laciniata Agardh. 2 P. vulgaris Agardh. 3 P. capensis Kuetzing. (1) P. laciniata = P. umbilicalis (L) J. Ag. f. laciniata (Light.) Thuret in Le Jolis' Liste (1864), p. 99—is a form of the common Porphyra of the North Atlantic and Mediterranean. (2) P. vulgaris = P. umbilicalis (L) J. Ag. f. vulgaris (Ag.) Thuret in Le Jolis' Liste, p. 99. This is also one of the forms of the common North Atlantic species. (3) P. capensis Kuetzing is a South African plant, here wrongly identified with P. columbina Mont. Harvey further states (loc cit.) that P. vulgaris and P. capensis occur together and are probably not different. It will be seen that Harvey deletes the original good species, P. columbina Mont., and inserts three species, two from the North Atlantic and one from the Cape of Good Hope. Now, as already has been noted, it was the tendency in recent years for algologists to restrict P. umbilicalis (L) J. Ag. in its various forms, P. vulgaris, P. laciniata, P. linearis to Northern waters; but we certainly have a form in New Zealand which closely approaches P. laciniata, and other plants can be found which in most respects match P. vulgaris and P. linearis. However, our plant presents minor differences. It seems therefore wiser to describe our form under a varietal name, viz., P. umbilicalis (L) J. Ag. var. Novae Zelandiae Lg. This is the more necessary as there is in constant association with the New Zealand plant in the same thallus, and to the ordinary eye quite indistinguishable from the Porphyra, a plant of a distinct genus, which I am naming Erythrocladia (?) insignis. Thus though we have in New Zealand the common English Porphyra known as the “purple laver,” and used as a popular remedy in England and Scotland for scrophulous cases, as a delicacy, and as a food by the poorer fishing classes, it has associated with it commensally and usually forming a large portion of thallus, a plant of a different genus, which may have different properties. It is thus impossible to obtain here purple laver in its pure form. I do not know what is the food value of the compound Erythrocladia-Porphyra fronds; but possibly they will be found to be quite as acceptable and just as useful as those of the true P. vulgaris. (C) J. Agardh (1877) p. 1, following Harvey lists P. vulgaris and P. laciniata only; but in (1882) p. 62 he created the new species P. nobilis for New Zealand, though he did not state if it was to replace one of the previously recorded species or not. I hope to show later that P. nobilis is only a form or state of P. columbina, and that the name must disappear, or appear only as a slight varietal state of the latter species. P. nobilis J. Ag. is founded on specimens collected by Dr. Berggren “ad oras Novae Zelandiae.” J. Agardh (loc. cit.) further revives Montagne's P. columbina for other specimens collected on the coasts of New Zealand, and the adjacent islands by Berggren.
(D) In 1899, Laing p. 61 following Agardh 1882 p. 62, records from New Zealand, P. nobilis, and P. columbina; and drops the North Atlantic forms of P. umbilicalis (L) J. Ag. recorded by Harvey, and in the Addendum No. 389 records P. subtumens J. Ag. (mser.). This is a nomen nudum and is described later in this paper for the first time. (E) Then in 1909 p. 503, Laing records for the Sub-Antarctic islands of New Zealand:— 1 P. perforata J. Ag. 2 P. nobilis J. Ag. 3 P. columbina Mont. P. perforata J. Ag. is a plant from the North Pacific, fully described by Hus (1902) p. 202. It is best known from California, but occurs North to Alaska and again probably on the north-east Asiatic coasts. The plant was identified for me (somewhat doubtfully) by A. Gepp, as occurring in the Sub-Antarctic Islands of New Zealand. “Whether P. perforata is right for the Campbell Island specimens, I cannot say for certain. It is as near as I can get at present.” (Extract from letter from A. Gepp under date November 24th, 1908). Later Prof. Setchell assured me that the plants corresponded exactly in external appearance with the North Pacific forms of P. perforata. Hence I have hitherto enumerated them as such, and as replacing the P. laciniata of Harvey. Closer examination enables me to state that they are not P. perforata. Whether this is the form described by Harvey as P. laciniata J. Ag. it is impossible to state with certainty, without access to the original specimens, but it is the only species on New Zealand shores commonly laciniate, and would almost certainly be in Harvey's herbarium. However, Harvey obviously gave the New Zealand Porphyras enumerated by him only a cursory examination. Thus he says of the Auckland Island forms, Hooker (1844) p. 193, that P. columbina differs from P. vulgaris in the rigid texture of the frond, and without further comment identifies it with the South African P. capensis. Similarly he identifies the New Zealand forms, Hooker (1855) p. 264, as P. laciniata J. Ag. and P. vulgaris Ag., but gives no detailed description. (F) In 1926, Laing following his previous determinations records in his list of marine algae the following species p. 146:— 145. P. columbina Mont. 146. P. nobilis J. Ag. 147. P. perforata f. lanceolata Setchell and Hus. 148. P. subtumens J. Ag. (nom. nud.) It is proposed now to show that P. nobilis is only a synonym for P. columbina; and, as already stated, that P. perforata is distinct from the New Zealand plant, and to provide a description of P. subtumens. Key to New Zealand Species of Porphyra. P. columbina, cystocarps large containing up to 256 or more carpospores, monoecious. P. umbilicalis, var. Novae Zelandiae, cystocarps containing normally 8, but sometimes 16 carpospores, monoecious.
P. subtumens, epiphytic or parasitic on D'Urvillea, cystocarps with 16 to 32 carpospores, monoecious. P. columbina Mont. Synonyms. P. capensis Kuetz.; Harvey (1847) i. p. 193; Harvey 1867 p. 715. P. nobilis J. Ag. (1882) p. 62; Lg. (1899) p. 61, No. 35; Lg. (1909) p. 504; Lg. (1926) p. 146, No. 145; de Toni e Forti (1923) p. 13. P. vulgaris, Harv. (1855) ii. p. 264. (?) P. Kunthiana. Kuetz. Phyc. gener. p. 383. I quote the description of Montagne with some of his comments, as it is rather inaccessible and as it will be necessary to refer subsequently to various points in it. Porphyra columbina Mont. P. frondibus gelatinoso-membranaceis aggregatis parvulis purpureo-violaceis, columbinis, orbiculatis crispato-undulatis granulis sub-quaternis. P. columbina Montag. Prodr. Antarct. p. 14; Endl. l.c. p. 19 Hab. in oris Aucklandicis ab ill. D'Urville inventa. Desc. Frondes ex una basi dilatata disciformi plures in caespitem congestae, tenuissime membranaceae, gelatinosae, orbiculares sesquipollares, margine lacero-crispato undulatae, minutissime regulariter violaceopunctatae, et sporidiis purpureis in acervos orbiculatos collectis aut effusis granulatae. Structura cellulae amplae bina granula violacea quarum singulum utriculo proprio inclusum videtur, foventes et ordine quaterno saepius dispositae. Sporidia granula nutritione s. vegetatione praeter modum aucta, 2-4 plo. crassiora accreta simul confusa purpurea sorosque effusos imprimis ad margines efformantes substantia tenuis, membranacea gelatinosa facillime dilaceranda. Chartam cui causa exsiccatione imposita fuit, conchyliatam ad ambitum amoene rediit eique praterea arctissime adhaeret. J. Agardh (1882) p. 70 gives the following diagnosis. “Porph. columbina (Mont. Prodr. phyc. ant p. 14) rupicola membranacea ex livido violacea pluripollicaris, fronde juvenili sessili supra basem reniformiter expansa obovato—oblonga marginis undulatis lobatisque, demum distromatica endochromatibus quaternatis quadrigeminis invicem distantibus, tetradibus limbo latiore ipsorum diametrum conspicue superante a proximis separatis, glomerulos sporidiorun singulis verticaliter elongatis, suo diametro plus duplo longioribus.” Neither of these descriptions is sufficient for present-day requirements and will have to be supplemented. Two points in Montagne's accurate account misled subsequent investigators. The first is his statement that the plant is small, only an inch and a half in length. Obviously the specimens collected by D'Urville were young or dwarfed, and other investigators looking for a small tufted form have overlooked the abundant specimens of P. columbina growing everywhere on the rocks between half-tide and high-tide marks on the open coast and in harbours throughout New Zealand. Another fact which no doubt has led to the same oversight was the original dis-
covery of the plant at the Auckland Islands, hence the tendency to overlook its existence in New Zealand. The plant does not usually adhere firmly to paper or discharge its colour, as stated, by Montagne, unless it is slightly decayed. Agardh points out that he himself has not seen the small tufted orbicular, purple violet fronds described and depicted by Montagne,* I collected mature plants exactly corresponding to Montagne's description at Moeraki in May, 1926. but suggests quite correctly that the form and magnitude may vary. The chief error in Agardh's description is his statement that the frond is two-layered (distromatic). It seems probable from his figures that his error has been due to his making of a section through the reproductive portion of the frond. (Tab. 11, fig. 65, t and 66 loc. cit.). These figures certainly suggest a section through the cystocarpic portion of the frond. The marked division between the upper and lower layer is the first reproductive division in the cystocarp, which remains permanent and well marked throughout subsequent changes. Species of Porphyra that are distromatic are placed by De Toni (1890) Syll. IV. p. 20 in the genus Wildemania; and in this he has been followed by a few algologists, but many do not recognize the distinction. However, I have not as yet found any distromatic species of Porphyra in New Zealand. Having thus, as far as I can, cleared up the chief points of difficulty in nomenclature, it remains now to give a more detailed account and description of P. columbina Mont. The Thallus.—The plant grows from a small fleshy umbilical disc a mm. or two in diameter; and gives rise to a number of long linear fronds with undulate crisped and folded margins, entire and slightly lobed (Fig. 1).† The photographs and micro-photographs are by Mr. C. M. Gray. The outer ends of the fronds are soon worn or torn off, and the fronds expand in breadth, so that we get a number of broad tufted, often folded fronds of somewhat irregular shape. These are usually much broader than high, so that the whole plant when pressed flat upon paper becomes approximately circular in outline, and is 10 cm.—20 cm. across (Fig. 2). In this form it is common in spring and early summer on rocks from high to about half-tide marks. It is not found in pools. As it grows older it may lengthen somewhat, and become more irregularly cut and lobed (Fig. 3), and assume a greater variety of shapes. The margin is usually erose or entire, but sometimes bears short blunt protuberances, simply forked, or papilliform. The long, narrow linear forms are to be found (near Christchurch) in August and September, along with a few of the previous year's plants, which usually occur near high-water mark, where they have been subjected less to the violence of the waves. The plant is, when fresh, olive-brown to green with reddish-brown margins in the sporocarpic area. It has less of the tan colour than is to be seen in P. umbilicalis var. Novae Zelandiac, but is similar to it in general appearance, with, however, a more crisped and irregular margin.
In smoother water and in suitable positions, e.g., where pendent from an overhanging rock and swayed by the tide, it may grow to a considerable length and become fairly regularly oblong. Occasionally through being torn, it may become somewhat laciniate; but this is not its characteristic form, as it is that of the following species P. umbilicalis, var. Novae Zelandiae. In quiet waters, such as those of a river estuary, it may reach 70—80 cm. in length, with a breadth of 30 cm.—40 cm. As it grows older and starts to decay, the olive green becomes more pronounced, the brown fades out, and after passing through a dirty sherry colour, it becomes green enough to be mistaken for a decaying Ulva. It is at certain stages very similar to P. umbilicalis var. Novae Zelandiae in appearance, and on the rocks can often scarcely be distinguished from it. Both in masses are dark brown-black, but there is usually more green in P. columbina than in P. umbilicalis var. Novae Zelandiae. When dried and kept in a herbarium for a few months, it changes to vandyke-brown, passes through a port-wine shade to a plum colour, or even to a lilac shade. It was this last shade that impressed Montagne and led to its specific name. Unfortunately, neither Agardh nor Montagne ever saw the plant growing, and so their descriptions of the colour must be taken to apply to the dead plant. The thallus is brighter and redder towards the margin where there are masses of cystocarps, and a dirty white when there are patches of antheridia. But even in a herbarium specimen one may find in the vegetative portion abrupt changes of colour from a dull yellow or brown to a purple, without apparently any change whatever in structure. This change does not, as it usually does in P. umbilicalis var. Novae Zelandiae, indicate any passage from one member of a commensal pair to another. It is possibly due to varying amounts of moisture in different parts of the frond. As it lies on the rocks, the thallus often becomes perforated; and as it becomes older, duller in colour, passing through a number of colours, until it reaches the dirty olive-green already referred to. It may be found at all seasons of the year from high-tide down to half-tide. It requires exposure to the air, but after a hot, dry summer it largely disappears from the rocks and either cannot be found at all, or only under overhanging faces. From September to January it may usually be found in immense masses covering the boulders and ledges, providing very insecure foothold for the walker, and constituting the chief vegetation of the area. Structure.—At the base, which is often paler than the rest of the plant, occur the typical rhizines, which closely compacted form the disc, consisting of the massed hyphal ends of the lower cells of the fronds. The disc is often more or less umbilical. The vegetative cells are usually highly characteristic, and generally enable the species to be determined from a patch of frond a few millimetres in area; but the shape and size of the cells and breadth of the surrounding gelatine vary considerably with the age of the plant, the position of the area relative to the base, the distance from the margin, and other conditions. As seen from the surface the irregularly-shaped endochrome fills nearly the whole of the lumen and shows, when fresh, an
average length of 20 mmm.—30 mmm., and breadth 12 mmm.—25 mmm. Between adjacent chloropasts the gelatine may be 5 mmm.—10 mmm. in breadth, but in some parts of the frond is greater or less. Occasional cells of much larger dimensions may be found. The shape of the cells varies much. When young they are often found in pairs, each cell being an oval, flattened on one side with its flat side towards its sister cell, but as they grow older the shape becomes more irregular, until they become oval, oblong, pyriform, triangular and even nearly square (Fig. 4). The distance between adjacent pairs becomes less, owing to the separation of the sister cells. Towards the margin they become slightly rounder, larger, and looser. The cellwall at first angular, 4—6 sided, owing to pressure, becomes afterwards rounder and more curved, and finally is invisible in the gelatine. In old and decaying specimens the mucilaginous interspaces become wider, and may amount to several times the diameter of the endochrome. However, the apparent width of the hyaline margin depends much on the method of preparation, being less in fresh material than in that which has been mounted in glycerine for some time. Towards the base the cells are usually more angled than elsewhere, and the breadth of the gelatine seen from above becomes again comparatively small. The thickness of the thallus when measured through a vegetative portion near the margin is 45 mmm.—60 mmm.; but it becomes much thicker in the cystocarpic portions. In section, the vegetative cells in the centre of the thallus are usually regularly rectangular, and often slightly concave on the shorter sides, 10 mmm.—25 mmm. in length, the thickness of course varying considerably with the method of preparation. Though usually rectangular and about half as long as broad the shape of the cells varies in different parts of the same specimen, being at times nearly square, or irregularly contracted in places. Towards the margin of the frond in the cystocarpic area, the cells are usually oval in section, or sometimes convex on one side and flat on the other. The measurements given are only to be used with circumspection, as those of the gelatine in particular depend to a considerable extent on the method of preparation, state, and age of the specimen; but nowhere after examining many specimens from many localities, have I found a distromatic frond. This species is sometimes parasitized by an Erythrocladia, which is perhaps the same species as that found in P. umbilicalis var. Novae Zelandiae to be described more fully later. The cells of the parasite are so like those of the Porphyra that it is generally quite impossible to distinguish them except in fresh specimens. Invagination takes place after the fashion subsequently described in Erythrocladia insignis; and I have even seen the cystocarps of the Porphyra apparently linked up by the processes of the Erythocladia. A process failing to penetrate an adjacent cell may be lengthened until it is 200 mmm. or more long, though only 5 mmm. or less in breadth. The species of Erythocladia parasitic in P. columbina presents certain minor differences from E. insignis; but so far I have seen nothing sufficiently distinctive to justify giving it a fresh name, and for the
present the two forms must be regarded as identical. P. columbina is only occasionally parasitized, and then only in a small portion near the margin of the frond. Reproduction.—The cystocarps and antheridia are scattered round the edges of the frond, and gencrally occupy an area of 1 cm. —2 cm. in breadth; but in older fronds the cystocarps may be found right across the surface of the frond, being much more numerous towards the margin. The antheridia chiefly occupy the marginal area for a depth of several mm. but irregularly-shaped antheridial patches are sometimes to be found in the cystocarpic regions. Quite young plants are fertile, and reproductive organs may be found at all times of the year. Mature cystocarps as seen from the surface are 75 mmm.—100 mmm. in length and about half that in breadth, in section they are about 100 mmm. with a varying thickness of gelatine on each side depending on the method of preparation. They are broadly oval in shape and usually contain about 32 surface divisions, but this number may be doubled, perhaps owing to the coalcscence of two adjacent cystocarps—usually they are 8 divisions deep — thus giving rise in some cases to as many as 512 carpospores in one cystocarp. As they become older they become more nearly circular in horizontal section, and the contents are finally aggregated without order; occasionally very large cystocarps are to be seen in which it is impossible to count the number of spores. (Figs. 6, 7.) The cystocarps are usually scattered, but sometimes closely appressed side to side, so as to form patches. The first divisions are cruciate, and remain distinct until the carpospores are almost mature. Other divisions are irregular, and are frequently more or less diagonal when seen in section. In addition to the ordinary vegetative cells, much larger and often colourless cells are inter-mixed with the cystocarps. These may be exhausted cystocarps. The antheridial patches are quite irregular in shape; but often rim the margins for a depth of two or three mm. from the surface in the cystocarpie region and with a length of several cms. They are colourless and do not enclose vegetative cells, though an occasional eystocarp is met with amongst them. They often appear as irregular enclaves in the eystocarpic region. The antheridium at first divides into a tetrad, then subdivides forming a pair of tetrads, and in some cases four tetrads are formed, thus giving 16 surface divisions. The number of tiers is usually eight; thus giving a total number of 128 antherozoids; but fewer divisions parallel to the surface may sometimes be found. (Fig. 5.) P. nobilis, a synonym for P. columbina. Having given a fairly full description of P. columbina, I shall now endeavour to show that J. G. Agardh's P. nobilis, is only a synonym for P. columbina. His description is as follows (J. Ag. 1882, p. 62):— P. nobilis (J. Ag. mscr.) rupicola membranacea sub-lilacino purpurascens pluri-pollicaris, fronde sensim inferne umbilicata, superne laciniata undulata monostromatica, endochromatibus demum
quaternatis, quadrigeminis invicem adproximatis, tetradibus limbo latiore hyalino diametrum endochromatis aequante a proximis separatis, parietibus cellularum vicinarum pressione mutua angulatis admodum conspicuis, sporidiis inordinatis plurimis glomerulos verticaliter ovales formantibus. In comparing this with his description of P. columbina it will be seen that the points of difference are the following:— P. columbina. P. nobilis. (1)Distromatic. Monostromatic. (2)Colour, “ex lurido violacea” “Sub-lilacino purpurascens.” (3)Width of gelatine. “tetradibus limbo latiore ipsorum diametrum conspicue diametrum conspicue superante a proximis separatis.” (3)“tetradibus limbo latiore byalino diametrum endochromatis aequante a proximis separatis.” (4)Cell wall (not described). (4)Parietibus cellularum vicinarum pressione mutua angulatis admodum conspicuis. Now I have dealt with all these points in my description of P. columbina. However, I should perhaps show here that none of them is distinctive. (1) P. columbina—if properly identified by me, is monostromatic and in this does not differ from P. nobilis J. Ag. (2) The colour of a Porphyra generally varies so much according to age, state, habitat, etc., that it cannot usually be employed as a specific determinant, except cautiously in conjunction with other characteristics. Some forms of P. columbina are on drying lilac, others pass through purple to dark red and brown. I cannot find any colour strains sufficiently distinct to separate P. nobilis from P. columbina. (3) The width of the gelatine surrounding the cells. This varies much, but particularly with the portion of the frond from which the area examined is taken and the age. There is little interspersed gelatine near the centre of the frond or towards the base. There is much more in old fronds and towards the margin. The character is quite insufficient to enable one to found a specific distinction on it. (4) The angularity of the cells and the distinctness of the cellwall. These also vary much. The angularity of the cells in the reproductive area is often pronounced and the cell-walls distinct. Their character also depend on the method of preparation of the frond, and the distinction made by J. Agardh is too slight to be of virtue for discrimination. I consider then that P. nobilis J. Ag. is only a state of P. columbina, and therefore P. nobilis J. Ag. must in future be regarded as a synonym for P. columbina Mont. I have, through the kindness of Dr. Kylin of Lund, received two microscope slides from specimens identified by J. Agardh as P. nobilis and P. columbina; and though these * For further discussion of colour see under P. subtumens.
slides do to some extent show the differences insisted upon by Agardh between the two species, I think as above shown that both slides represent only different states of the same species. Since writing the above, I have received from Dr. G. Hamel, of Paris, to whom I sent specimens of our New Zealand Porphyras, a letter under date 26th August, 1927, which further confirms my view of the identity of the two species. A portion of the letter I quote:— “Les petits échantillons (P. nobilis No. 1980) correspond bien au type du P. columbina Mont. Je crois come vous que le grand échantillon (P. nobilis, No. 1952) n'est qu'une forme de la meme espèee. J'appelle le tout P. columbina Mont.; je pense que le P. Kunthiana Kutz n'en est pas different. Vous trouverez une bonne description de cette dernière espèce dans Howe Mar. Alg. of Peru. Les characteristiques sont grand épaisseur de la fronde, organes sexuels en plages melangées, spores et spermaties nombreuses, cellules vegetatives presque carrées.” As to the identity of P. columbina, Mont. with P. Kunthiana Kütz, I can offer no opinion as I have no specimen of P. Kunthiana, nor have I access to Marshall A. Howe's work on the Marine Algae of Peru, so that the matter must be here left in abeyance. However, I have included P. Kunthiana with a (?) amongst the synonyms. Localities.—Antipodes (Cockayne!) Campbell Island, Aucklands, Snares, Dunedin (Lawyer Head, Black Head, Hoopers Inlet, etc.), Moeraki, Lyttelton (Summer, Taylors Mistake, Governors Bay, etc.), Gore Bay, Kaikoura, Wellington (Lyall Bay, Mahanga Bay, Wellington Heads, etc.). The northernmost points from which I have noted specimens is Mongonui. The plant is no doubt abundant in suitable localities all along the New Zealand coasts: but so far does not appear to have been identified outside New Zealand, unless it is identical with the South American P. Kunthiana. Porphyra subtumens (J. Ag.) Lg. This is a very distinct little species abundant on D'Urvillea antarctica at certain seasons of the year. Many years ago I sent specimens of it to J. Agardh at Lund, who returned it under the name of Porphyra subtumens, under which name I recorded it (1902), p. 358 No. 389. Apparently the species has never been described, so Porphyra subtumens still remains a nomen nudum. Porphyra subtumens (J. Ag.) Lg. Species Porphyrae monostromatica, monoica, cndochroma, aliquando sensim granulata in D'Urvillea antarctica insidens. basi incolorata, cuncata, thallo expanso, rotundato, lobato, 10 cm.—15 cm. longo et lato, crassitudine 25 mmm.—35 mmm. Margine crispata, irregulariter lobata dentataque, cellulis irregulariter ovalibus, 20mmm. —30 mmm. longis, 15 mmm.—20 mmm. latis, cystocarpis a facie visis quaternis saepissime divisis, et in quattuor stratis dispositis, antheridiis a facic visis sedecim in quattuor vel raro in octo stratis dispositis.
General Description. As I have recognised the specific name subtumens in my lists, though hitherto only a nomen nudum, I presume I must continue to use it. However, I have no idea why Agardh applied the name to this plant. I can find nothing to suggest it, unless that the plant is apt to swell up and disintegrate when placed in various mounting fluids. The Thallus. — The plant is epiphytic or possibly parasitic on D'Urvillea antarctica Cham. I have not so far been able to trace any further connection between the two species than the fact that the Porphyra puts out rhizines of the type normal to the genus, which penetrate into the thallus of the D'Urvillea. Whether they act as haustoria, I do not know. There is no apparent reason why the plant should not nourish itself. The smallest plant examined was 2—3 mm. across, rounded in shape, and slightly stipitate, and consisted chiefly of rhizine emitting cells. The base is colourless and cuneate. Older plants are expanded into a thallus, which is irregularly lobed and toothed, and grows up to 12 cm. and 15 cm. in length and breadth. It is usually more or less rotundate in outline. It dries to a bright pink puce or red colour and adhercs closely to paper, becoming much wrinkled in the process. In the fresh specimens the colour is similar to that of the dried, but not so bright as it later becomes. It is therefore quite readily distinguished from the other New Zealand species by colour alone. It is a transient summer-growing plant being found chiefly in the months October to March, and so far as I am aware not to be found at all in the winter months. (Fig. 8.) Minute Structure.—The frond is monostromatic, and tenuous, 50 mmm.—75 mmm. in thickness in a glycerine mount; but only about half that thickness in a balsam mount, where there is no swelling of the gelatine. In section the cells are usually oval, but vary considerably, being sometimes square, sometimes twice as high as broad, round, and of other forms. They are from 20 mmm.—25 mmm. in height, with a varying amount of gelatine on each side, so that the whole section may be not more than 30 mmm.—35 mmm. in thickness. The endochrome fills the whole lumen of the cell, and sometimes but not always appear granular. It is unlikely, however, that this is the case, and the apparent granulation may be due to projections or irregularities on the surface of the chromatophore. The cells seen from the surface are irregularly rectangular-oval or rotundate about 12 mmm.—18 mmm. in length and breadth. (Fig. 9.) Reproduction.—The plant is monoecious, and the greater portion of the frond becomes reproductive. The antheridia are 25 mmm.—30 mmm. in length and rather less in width with a maximum of 16 surface divisions, and eight layers deep. It would seem probable that the divisions of each tier at right angles to the frond takes place successively, and the spermatia in the first layer escape before the second layer is subdivided. At least the antheridia, when seen from the side, show only the eight divisions parallel to the surface of the frond, and not those at right angles to it. (Fig. 10.)
The cystocarps are rather larger than the antheridia, and show 4 to 8 surface divisions, and usually 4 in depth, thus giving 16 or 32 carpospores. They show the same characteristic as the antheridia, i.e., at first only the surface layer is divided at right angles to the frond, the three remaining tiers when seen from the side appearing undivided. (Fig. 11.) With regard to this species Dr. Hamel writes 26th August, 1927, in a latter from which I take the liberty of quoting. “Je crois que ce que vous appelez P. subtumens est le véritable P. nobilis J. Ag. voici ce que J'en dis dans mon article [an article to be shortly published.] “Bien que J. Agardh dise que son P. nobilis cst rupicole, un echantillon conservé dans l'herbier Thuret (Algae Muellerianac, curante J. Agardh, distributae) ct provenant du cap Saunders, New Zealand, est épiphyte. (In a foot note, “épiphyte sur un Schizymenia”.) Comme l'indique J. Agardh, la couleur de cette espèce rapelle celle du P. miniata; elle est cependant d'un rouge vineux un plus foncé et plus terne. Les échantillons ont de 3 à 5 cm.; deux de'entre eux sont orbiculaires, à marge assez fortement plissées, le troisiéme, qui est épiphyte, est plus allongé et très cnroulé en spirale. Le tissu assez serré est formé de cellules arrondies d'environ 10 mmm. de diametre et la fronde montre une épaisseur de 30 a 45 mmm. Echantillons steriles.” I would like to submit a few comments on the above. Now I think I have given sufficient reason already for regarding P. nobilis as a synonym for P. columbina, and I can see no resemblances in the above description to P. columbina. Consequently I cannot think that Dr. Hamel is right in considering his specimens from Cape Saunders to be Agardh's P. nobilis. The description on the whole, however, corresponds well with my P. subtumens. The small cells, the thin tissue and the colour certainly suggest this. Against it is the fact that one at least of the specimens was found growing on a Schizymenia. Now one would certainly expect to find P. subtumens on the D'Urvillea at Cape Saunders, but I have not seen it on Schizymenia, and its occurrence on species of this genus must be rare. I have a specimen of P. miniata from Greenland which exactly matches in colour some young plants of P. subtumens from Akatore, and the ordinary colour of dried specimens of P. subtumens might well be described as “un rouge vineux un peu plus foncé et plus terne.” It seems, too, probable that Agardh has at one time (1882) confused the two species P. subtumens and P. nobilis (= P. columbina); it was some years later (1900) when he named my specimens as P. subtumens, and probably up to that time he had placed his specimens of P. subtumens with those of P. nobilis, and had not submitted them to any close examination. There can be no doubt that the plant defined for me by J. Agardh as P. subtumens is the epiphyte on D'Urvillea, and that P. nobilis J. Ag. agrees in all respects with P. columbina Mont. except in colour. The confusion in colour no doubt resulted from the fact that Agardh had mingled the two species in his herbarium. Certainly the fragment of P. nobilis Ag. sent me by
Kylin is P. columbina, not P. subtumens, so I think P. subtumens must stand, and P. nobilis remain a synonym of P. columbina. Localities. — Stewart Island, Akatore (Otago), near Dunedin (various localities), near Christchurch (various localities), Gore Bay, doubtless common wherever D'Urvillea occurs as far North as Gore Bay. Found only in summer and autumn, a transient species. Erythrocladia (?)-Porphyra, A Case of antagonistic commensalism. Rosenvinge (1909) p. 71 established a new genus of parasitic Bangiales under the name Erythrocladia and described two species, E. irregularis and E. subintegra, found in plants of Polysiphonia urceolata. Rosenvinge's description of the genus is as follows:— Thallus horizontaliter expansus, e filis ramosis, aliis algis adfixis radiatim egregientibus, initio inter se discretis deinde in discum tenuem unistratosum confluentibus constans. Crescentia filorum apicalis. Sporangia eodem modo ac in genere Erythrotrichia in cellulis intercalaribus vel rarius terminalibus gignuntur. Generatio sexualis adhuc ignota. Now there is growing in and with a common species of New Zealand Porphyra a plant which presents most, if not all, of the characteristics of this genus, and which for the present at least may be placed in it. When the sexual forms of the European species of Erythrocladia are discovered, it may of course be found that the New Zealand and European plants are quite different. I propose to call the Porphyra associated with it in New Zealand P. umbilicalis var. Novae Zealandiae, as though approaching such forms as P. laciniata, and P. perforata of the Northern Hemisphere it appears to be sufficiently distinct; and it is certainly much safer in such doubtful cases as past experience has abundantly shown to regard the local form as different. The Erythrocladia I propose to name E. insignis. In certain of its forms it is similar in construction to E. irregularis of Rosenvinge, but displays a much wider range of structure than the latter, so far as at present known. The following is a condensed description of E. irregularis as given by Rosenvinge. The plant forms irregular spots of up to 100 mmm. in diameter on the surface of the host plant. It consists at first of branched filaments whose branches are mutually entirely separate. The primary filament grows out in two opposite directions, and gives off branches at both sides. These branches grow out and branch further, and in the more developed plant the filaments are therefore radiating in all directions in the horizontal plane, and the filaments are then more or less fused together in the central part of the frond. The filaments show apical growth, and transverse walls appear only in the terminal cells. The branches usually arise in the sub-terminal cells, sometimes also in cells nearer the centre of the frond, but the terminal cell is only very seldom ramified. The sporangia are cut off in the ordinary vegetative cells, in a similar manner as in the genus Erythrotrichia, by a more or less oblique curved wall (Rosenvinge 1909, p. 72 and 73). Now a description of the New Zealand compound plant will enable a comparison to be made. Plants were collected in all stages at Timaru on August 21st, 1927. The smallest consisted of discs 3 mm.—5 mm.
Fig. 1.—Porphyra columbina Mont. Young linear forms. Fig. 2.—Porphyra columbina Mont. Intermediate circular stage.
Fig. 3.—Porphyra columbina Mont. Small portion of old plant. From Heathcote Estuary.
Fig. 4.—Porphyra columbina. Vegetative structure (typical) × 150. Fig. 5.—Porphyra columbina. Antheridia × 150.
Fig. 6.—Porphyra columbina. Young cystocarps × 75. Fig. 7.—Porphyra columbina Mature cystocarps × 150.
Fig. 8.—Porphyra subtumens, mature plants.
Fig. 9.—Porphyra subtumens. Vegetative structure (typical) × 75. Fig. 10.—Porphyra subtumens. Antheridial area (x 125). The deliquescent nature of the thallus is obvious in the slide. Fig. 11—Porphyra subtumens. Cystocarps (× 300).
Fig. 12.—Porphyra umbilicalis with Erythrocladia insignis. Portion of broad form, Timaru, September 1927.
Fig. 13—Porphyra umbilicalis with Erythrocladia insignis. Laciniate form, Timaru, August, 1925.
Fig. 14.—Porphyra umbilicalis, var. Novae Zelandiae. Rhizines at the base, × 140. Fig. 15.—Porphyra umbilicalis var. Novae Zelandiae. Typical vegetative portion, with much gelatine, × 100.
Fig. 16.—Porphyra umbilicalis var. Novae Zelandiae. Older vegetative portion with little gelatine, × 120. Fig. 17.—Porphyra umbilicalis var. Novae Zelandiae. Mature cytocarps, × 200.
Fig. 18.—Erythrotrichia ciliaris (?) on Zostera sp.
Fig. 19.—Erythrocladia insignis. Invagination. A lense will shew invagination going on in area surrounded by the arborescences, × 75. Fig. 20.—Erythrocladia insignis. Cell clusters, surrounded by arborescences, × 75.
Fig. 21.—Erythrocladia insignis An arborescences, × 200. Fig. 22.—Cells of Erythrocladia insignis streaming into an area, already occupied by Porphyra. The smaller darker cells are those of Erythrocladia, the larger paler ones are those of P. umbilicalis, var. Novae Zelandiae, × 150.
Fig. 23.—Erythrocladia-Porphyra, spinulose margin, × 75. Fig. 24.—Erythrocladia-Porphyra, erose margin, × 100.
Fig. 25.—Erythrocladia insignis. Typical portion of the thallus, without invaginations (× 125). Fig. 26.—Erythrocladia insignis. Cystcarps (?) (x 150).
across, the longest measured was over a metre in length. A description of one of the smallest plants will probably render what follows more intelligible. It formed a small dark-brown thallus some six mm. across. When found it was growing in a crevice in a boulder of doleritic rock on the north mole at Timaru near high-water mark. It was mounted fresh in sea water and examined. The thallus was approximately reniform with a deep sinus at the base, and consisted of two distinct types of cells, those of the Porphyra a pale yellow-brown, almost tan-coloured, and those of the presumed Erythrocladia dark purple found in minute perforations in the thallus and also in the substance of the frond, sometimes solitary, or at the extreme base mingled in large numbers with those of the Porphyra. It may of course be argued that the purple and the brown cells represent different phases in the growth of the cell in one species. I shall discuss this possibility briefly and give the arguments pro and con. In favour of this hypothesis are the following facts: (1) In P. columbina, as we have already seen (p. 41), there is often an abrupt transition in colour from one portion of the thallus to another without however any difference in form, structure, or size of the cells. (2) Even in the plant we are describing such colour-changes occur, without any other apparent specific differences, or often with slight differences only (a). Thus I have observed similar colour-changes appear in the cystocarps, adjacent groups being tan and dull purple, but as I could trace no difference in construction, I concluded that all the cystocarps belonged to one plant and to one species, and (b) the brown cells undoubtedly do turn purple with drying, and also under other conditions, and (c) in other parts of the frond there are abrupt colour-transitions with only small changes in the size of the cells and the amount of gelatine surrounding them, though here we have probably to do only with cells of the same species in different stages of growth. These facts might seem to show that we are dealing with a single species, which chameleon-like changes its colours with its habits. Obviously colour-contrasts without differences in structure are here valueless for taxonomic purposes. But, on the other hand, in other parts of the plant we find the same colour-changes correlated with such wide differences in structure, form and size, that we can no longer regard the different groups of cells as belonging to the same species, and here the colour seems to be of taxonomic value. Assuming, for the sake of convenient description, that the purple cells as a rule belong to Erythrocladia and the brown ones to Porphyra, the following differences are seen to be correlated with the colour: (1) The Erythrocladia cells are much more rounded, and girt by wider interspaces of gelatine than those of the Porphyra. Often the differences in form are very marked. The cells of the Porphyra are usually irregularly rectangular (Figs. 15, 16) 20 mmm.—30 mmm. in length and fit closely together with very little mucilage. Those of the Erythrocladia, as seen from above, are usually rather smaller in size, oval or with rounded angles, but sometimes owing to compression they become very irregular in shape, and then they may become triangular, pyriform or even crescent shaped (Fig. 25). Solitary intrusive cells of the Erythrocladia, often much narrower and linear, are frequently to be seen wedged in between the
cells of the Porphyra, and strewn through the thallus (Fig. 22). (2) The strange invagination process and the accompanying developments never take place amongst the brown cells. At times one of the processes, however, may penetrate a brown cell, or in some way a brown cell comes under the influence of a neighbouring group of purple cells; it then changes colour through pink to purple, and behaves to all intents and purposes as one of the Erythrocladia group. Commonly, however, invagination takes place only between purple and purple, and not between brown and brown. It is therefore to be regarded as a structure belonging to the Erythrocladia and not to Porphyra. (3) The purple cells are usually associated with a spinulose margin, and the Porphyra with an erose or entire margin. (4) There may be seen cut off from purple cells, others which have all the appearance of gonidia as described by Rosenvinge for Erythrocladia. (5) Associated with the Porphyra type of cells are cystocarps, antheridia and gonidia which appear to correspond exactly with those described for Porphyra umbilicalis. (6) If it be argued that the purple and brown cells represent different stages in one species, the purple being the younger and therefore the smaller, one would expect in such a case to find cells in transition between the two groups; but these are not to be found. No purple cells so far as I have observed ever turn brown, but brown cells, under the influence of a purple group may be seen changing colour, there it appears to be not a normal but an abnormal change. (7) The process of invasion of the Porphyra area by the Erythrocladia can often be clearly followed. Streams of Erythrocladia cells penetrate the area occupied by the typical cells of Porphyra, surround them, and form a network about them. The Porphyra cells turn pink and apparently shortly disappear (Fig. 22). In this case there is no invagination, the invaginating cells usually being found in open areas in the Porphyra thallus, or in areas already taken possession of by the Erythrocladia. Taking all these facts into consideration, I am at present of the opinion that we have here to do with a case of antagonistic commensalism, in which an Erythrocladia is closely united with a Porphyra. It is true that as long as I was working with dried specimens, I hesitated to come to this conclusion; but it was the examination of fresh specimens with their remarkable colour-contrasts that led me to arrive at it; and it is on the assumption that the purple cells are those of Erythrocladia, unless otherwise indicated, and the brown cells in fresh specimens are always those of Porphyra, that I now proceed with the description of the specimens obtained at Timaru. Doubtless this conclusion may not always be accurate, for as we have already seen the cells of P. umbilicalis var. Novae Zelandiae sometimes are red, but in the main it is a sufficient guide for the description now to be given. In the small specimen described there were already scores of isolated cells of Erthyrocladia, and at least a dozen patches with 10—20 or more cells, and in addition a large patch round the sinus at the base emitting rhizines similar to those of the Porphyra (Fig. 14). Indeed, the attachment disc consisted rather of Erythrocladia than of Porphyra. I do not know which constituted the original plant;
but as the Erythrocladia is elsewhere known as a parasite or epiphyte, it seems better to speak here as if we were dealing with a case of invasion of the Porphyra by the Erythrocladia, and to regard the thallus as the product of a conjunctive or antagonistic symbiosis; for certainly the Erythrocladia seems to displace the Porphyra. At the base the Porphyra cells are larger than elsewhere, and often contain when fresh a green colouring matter (? chlorophyll undisguised) and as usual a large white pyrenoid (Fig. 14). The Erythrocladia has its usual cells of dark purple. The Porphyra cells are here 15 mmm.—30 mram. long, provided with rhizines, and are separated from the adjacent cells by gelatine 1.5 mmm.—2.5 mmm. in breadth. The average breadth of the cells is 10 mmm.—25 mmm. The cells of the parasite are 10 mmm.—25 mmm. in length, and 10 mmm.—15 mmm. in breadth. (A note should perhaps be inserted, that these are the dimensions as measured in fresh specimens mounted in sea-water. These seem to me to be the only correct dimensions. If mounted in a medium containing glycerine, the jelly in particular becomes much swollen, and the cell-dimensions somewhat increased. If passed through alcohol and xylol mixtures as for sectioning, the dimensions, particularly that of the jelly, are much reduced. Consequently, in this paper the dimensions given are always where possible those of the fresh specimens mounted in sea-water.) The margin of the Erythrocladia is irregularly microscopically spinulose (Fig. 23); and the terminal cell in a spinule is triangular. The margin of the Porphyra is either completely entire, or slightly erose and irregularly bitten with minute rounded lobes owing to the action of weather and waves (Fig. 24). I have found it with the cells adjacent exactly match a specimen of P. umbilicalis var. laciniata collected in Halifax Harbour, Nova Scotia, by the well-known American algologist Marshall A. Howe. Indeed, I could find no point of distinction between them; but in our specimens cells of either Porphyra or Erthyrocladia may be found in either type of margin; nor does it appear to be necessarily the case in such examples that when the Porphyra occurs with a spinulose margin, it has always displaced Erythrocladia, or when Erythrocladia appears with an entire margin, it has necessarily displaced Porphyra as might be assumed to be the case. Nevertheless the Porphyra type of cell is usually associated with the entire or erose margin, and the Erythrocladia with the spinulose margin; and the replacement of one form by the other obviously must frequently take place; thus we may find an invading oval cell in the spinule, which has replaced the normal triangular one. A further distinction between the cells of the two species is that the amount of gelatine round the Erythrocladia cells is greater than, that round the Porphyra, and, in the case of the former, swells much more in glycerine than in the case of the latter. Taking the colour in the fresh specimen as a guide, we find that the relative amount of each species varies much in the compound frond. Thus one specimen, irregularly oblong and much laciniate, contains only a few basal Porphyra cells with rhizines, and one or two narrow patches of Porphyra a cm. or two in length, in the upper third of the frond; another plant 35 cm. long much laciniated contains through its centre, and for about a third of its width, a strip
of Porphyra which rarely reaches the margin. A third plant of the same length is about 20 cm. wide without laciniations broadly oval in outline, and appears to contain only microscopic amounts of Erythrocladia in the form of arborescences (to be defined later). In a fourth plant much laciniated of about the same length as the two previous, I have found only a few cells of Erythyrocladia amongst the large rhazine-bearing green cells at the base, and I am not sure of the identity of those. In dried plants of uniform colour it is generally possible to distinguish the two areas by the amount of glaze on the surface. The Porphyra is highly glazed, and the Erythrocladia dull or only slightly glazed. The reproductive portion of the Porphyra, however, is less highly glazed than the vegetative portion, so that this distinction can here only be applied in conjunction with microscopic tests. The greater amount of irregularity in the cells of the Erythrocladia is, then, usually sufficient to identify them; but a number of remarkable structures it displays will be described in more detail when we come to consider the species. I conclude, therefore, that we have here to do with a thallus compounded of Porphyra umbilicalis (forma), and what is perhaps an asexual and sexual form of a species of Erythrocladia. I am by no means sure that my interpretation is correct; but at present I cannot put forward a better one. In addition to the one given the following have been considered and rejected. 1 That the thallus is a remarkable new species of Porphyra compounded of sexual and asexual plants. 2 That the thallus contains only a sexual form of Porphyra and asexual form of an Erythrocladia; but this was held only while some of the facts now disclosed were still unknown, and I do not at present think that it is worth further consideration. 3 That the plant is a Porphyra, with structures due to disease. Now I do not propose at this stage to discuss the various points of view further; but if they are borne in mind during the reading of the subsequent detailed descriptions, readers will I hope be able, by the aid of the microphotographs, to form their own opinions on the matter. The theory adopted does not perhaps solve all the difficulties; the weakness lies in the fact that I am not quite certain that I have isolated the sexual form of the Erythrocladia. If what I take to be the cystocarps of the Erythrocladia are really the gonidia of Porphyra, then my theory falls to the ground; but in the absence of further literature it is difficult to decide this question. However, the general identity of the Porphyra with the Northern P. umbilicalis can scarcely be doubted. Occasionally what appear to be pure specimens of P. umbilicalis are to be found. These when dried for a year or two turn to an old-rose-colour, and are glazed. They sometimes display the form of the common P. vulgaris, and are much brighter in colour than is the thallus of the mixed species and much glossier. The laciniate forms almost invariably contain both genera.
Porphyra umbilicalis J. Ag. var. Novae Zelandiae Lg. var. nov. Synonymy for the New Zealand forms- P. laciniata, Ag.; Harvey (1855) ii, p. 264. P. perforata J. Ag.; Lg. 1909, p. 503. P. perforata J. Ag. f. lanceolata Setchell and Hus.; Lg. 1926, p. 145, No. 147. P. umbilicalis (L) J. Ag. var. Novae Zelandiae in thallo unacum Erythrocladia insigni existens, margine undulata et minutissime spinulosa ant laevi erosaque. Frons monoica, antheridiis marginem (2 mm.—3 mm. latis) occupantibus, sporocarpia sine cellulis vegetativis in area sporocarpica, et frequenter antheridiis inmixta. This variety has now to be separated from P. perforata J. Ag. (1882), p. 69; and more fully described by Hus (1902), p. 202; and from P. umbilicalis var. laciniata. When dried it is indeed very difficult to distinguish them from either of the above without microscopic examination. The spinulose margin, the cystocarpic areas sometimes densely packed to the exclusion of vegetative cells, the frequent presence of antheridial patches in the cystocarpic areas and of cystocarps in the antheridial area, are points of distinction that separate it from both of the preceding, and will be sufficient to distinguish it as a variety from P. umbilicalis var. laciniata. It may be further distinguished from P. perforata. According to J. Agardh P. perforata is distromatic; but Setchell and Hus have shown that this is not so. Further, the figure given by them (Hus, 1902, p. 236, fig. 4a) shows a markedly different thallus from that seen in our plant, where the amount of jelly even in glycerine mounted specimens is not more than ¼—¼ the width of the endochrome, and is often less. Hence the name of P. perforata hitherto used by myself for this species will have to be rejected. However, the moat important characteristic of var. Novae-Zelandiae is the usual association with it in the same thallus of plants of Erythrocladia insignis. Forms of Thallus and Colour. — The young plant has already been described under Porphyra-Erythrocladia. From it there is usually developed a long narrow linear strip, though other forms may sometimes be seen. Thus a number of young specimens obtained at Taylors Mistake (near Christchurch) in July were 10 cm.—13 cm. long and only 5 mm.—10 mm. broad; but as the plant grows the relative breadth increases and several fronds may grow up from one base. (Fig. 12.) At Timaru, in September, specimens up to a metre in length could be obtained, with a width of 20 cm. or more. These larger specimens are usually irregularly laciniate, proliferous from the margin (Fig. 13). There is no uniformity in the shape of the mature plant, but it can usually be distinguished by its greater length and more divided thallus from P. columbina; and it has, as it lies on the rocks, more of a brown-red tinge in the thallus when viewed by reflected light, where P. columbina similarly viewed displays a certain amount of olive-green. However, the redder colour of P. umbilicalis var. Novae Zelandiae is no doubt due in large measure to the presence in it of Erythrocladia insignis.
Both species after a hot, dry summer disappear, and between December and June P. umbilicalis var. Novae Zealandiae sometimes cannot be found in its usual habitats. It is an annual, but reaches maturity in six weeks or two months after its first appearance, and so there may be several generations in the course of a year; but on this point I have no definite information. On drying, the plant passes through an almost indefinable series of shades—amber, burnt sienna, brown-purple to plum-colour. It does not show the lilac tinge of P. columbina, and remains a brighter and redder colour in the herbarium. The antheridial areas are colourless, and the cystocarpic portions much redder than the vegetative. Minute Structure.—The plant is monostromatic 75 mmm.—100 Pimm, in thickness in a glycerine mount with cells usually oblong in section up to 25 mmm.—30 mmm. in length, somewhat irregular in outline, and 15 mmm.—20 mmm. in breadth. The rest of the thickness is made up of jelly. The relative amount of jelly in fresh specimens is probably considerably less; but as fresh materials cannot be sectioned, it is not possible to give accurate measurements in this respect. The cells vary considerably in height, and though usually fairly regularly oblong with rounded corners are sometimes twice as deep as broad, and sometimes nearly as broad as deep, but they are on the average not nearly so square as those of Erythrocladia, and not so irregular. A portion from the centre of the frond, mounted fresh in sea-water and viewed from above shows cells of a dull-yellow to amber-brown in close contact with each other, practically without visible mucilage, irregularly rectangular to oval in shape, sometimes 5-6 sided, length 15 mmm.—25 mmm., breadth about half the length (Fig. 16). Towards the base the frond becomes greenish, and the cells more oval and larger, and there is more gelatine. For dimensions of basal cells, see p. 49. Towards the margin the cells are similar to those in the centre of the frond, but tend to elongate somewhat and to arrange themselves in lines parallel to the edge of the frond. Reproduction.—The cystocarps are densely packed together across the surface of the frond, and usually without vegetative cells. Enclaves of antheridia are sometimes to be found in the cystocarpic area; but usually the antheridia are to be found along the margin as in other species. In fresh materials the cystocarps are brown or pink 20 mmm.—30 mmm. in length, and 15 mmm.—20 mmm. broad, and of the same colour as the vegetative cells, and therefore not readily to be distinguished without microscopic examination. In this respect they are markedly distinct from those of P. columbina. Amongst them may occasionally be found large pale-yellow cells which are possibly dead or undivided cystocarps. As the plant becomes mature the cystocarps are so appressed together as to become almost indistinguishable. In younger areas there are many undivided carpogonia. The usual number of divisions is 4, but occasionally 8 may be found; and with 2 tiers in depth this gives the ordinary number of carpospores as 8; but they may I think be occasionally 16 (Fig. 17). There are occasional groups of cystocarps
in the anthcridial area. The thallus does not show thickening here as in P. columbina, and is usually about 75 mmm. deep in a glycerine mount, the cystocarps being 30 mmm.—35 mmm. in height. It is not uncommon to find among the cystocarps, a solitary arborescence of Erythrocladia (v.p. 57) or even solitary cells of the same plant. The antheridial area is typically marginal 2 mm.—3 mm. wide, entire and not spinulose. The antheridia which are colourless are somewhat smaller than the cystocarps 15 mmm.—20 mmm long, and about the same in width, being more nearly square than the former, which are approximately rectangular. As seen from the surface, the antheridium divides in 4, occasionally into 8, and rarely into 16 surface divisions. In section two, 4 or even 8 tiers are seen. The common number of spermatia is 32; there may be 64, or rarely 128. No vegetative cells are to be seen among the antheridia, but there axe occasionally to be met with large nearly colourless solitary cells, oval or circular, whose significance is unknown to me. Localities.—Dunedin (Black Head, St. Clair Tomahawk, etc., W. A. Searfe!), Timaru, Christchurch (Governors Bay), Purau, Stunner, Gore Bay, Wellington (Mahanga Bay, Lyall Bay). Doubtless it is common along the coast, though not yet identified. My best specimens come from Timaru. Apparently it largely disappears in the winter months. Erythrotrichiaceae. Gonidia arising in special monosporangia, cut off by a curved wall in a vegetative cell. Erythrotrichia: Frond erect filiform. Erythrocladia: Frond consisting of creeping branched filaments, more or less confluent to a monostromatic disc. Erythrotrichia ciliaris (?) (Carm.) Batters. The following description is quoted from de Toni (1924), p. 15: Erythrotrichia ciliaris (Carm.) Batt. in Journal of Botany, 1900, p. 374. Frondibus obscure purpureis, 500—800 mmm. longis, 10—30 mmm. latis (in speciminibias aliis 1—2 mm. longis, 10—200 mmm. latis), numerosis a disco monostromatico exsurgentibus, disco 20 mmm. rotundato, 50—200 mmm. diam. aequante, cellulis rotundatis polygoniis, 15—24 mmm. diam. aequantibus; sporis circ. 18 mmm. diam. metientibus. Now Erythrotrichia ciliaris is a little known and not well-understood species, recorded by de Toni only from Great Britain. It has been confused with E. Bertholdii and other species, and it seems most unlikely that it should be found in Great Britain and New Zealand and not in intervening districts. However, there are one or two casual notices of it elsewhere. Reinbold, Deutsche Sudpolar Expedition (1901-03) doubtfully records it from New Amsterdam; and states that it is known from tie coast of Europe, The Cape of Good Hope, Australia, and Martinique A. and E. S. Gepp (Journal of Botany, Dec. 1905) “Some cryptograms from Christmas Island” (Indian Ocean) also list it. But some of these localities are undoubtedly questionable. Hook and Harv., 1867, p. 716 record it from Cook Strait, “parasitic on loaves of Zostera, Lyall,” under the following description.
”Bangia ciliaris.—Filaments minute, simple, straight, ½ in. long, variable in breadth, compressed, purple, sometimes expanding and leafy in the middle; cells in 2 rows except, where expanded, globular.” I also found what is perhaps the same plant growing on leaves of Zostera in Akaroa Harbour, June 2nd, 1904; and on sending specimens to Major Reinbold he returned it as Bangia ciliaris, hence the plant appears in my list (1926), p. 146, No. 144. Further examination shows the species arising from a disc closely adherent to the Zostera. Now the genus is divided into two sections, according to the absence or presence of a disc. This brings our plant into the group possessing a disc with E. Soryana, E. ciliaris, E. polymorpha, and several other species. At present I have only dried specimens to work with, and cannot define the species sufficiently to identify it with certainty. Harvey's description, however, appears to be correct so far as it goes. The filaments which in the first stage consist of a single row of cells, expand and become “leafy” in the middle. This seems to suggest E. Boryana rather than E. ciliaris. E. Boryana is a more widely distributed species than E. ciliaris, being found in the Mediterranean as well as in the North Atlantic. However, it is most probable that on further examination our species will be found to be now. I have not seen the monospores. The plant grows up to 10 mm. in length and may be 1—2 mm. wide. The cells vary in relative length and breadth, sometimes broader than long, or again longer than broad. They may measure as much as 20 mmm. in length or breadth, but are usually smaller, and be as small as 5—10 mmm. in length and breadth. The cells can scarcely be called globular; but are more often rectangular. Our plant, judging” from the description in de Toni, seems to be larger than the true E. ciliaris, and than most of the species described. (Fig. 18.) Erythrocladia (?) insignia, Lg. sp. nov. Erythroeladia (?) species in Porphyra laciniata var. Novae Zelandiae, et in Porphyra columbina habitans. Thallus primo singularium cellularum stratum monstrans deinde cellulae inter se invaginantes discum crassum monostromaticum form antes filis ramosis radiatim egredientibus ant inter se discretis sine disco. Gonidia codem modo ac in genere Erythrotrichia in cellulis intercalaribus gignuntur, generatio sexualis Porphyrae similis. Minute Structure.—The general characters of the thallus have already been described in dealing with P. umbiticalis var. Novae-Zelandiae, and do not require further attention here. There are, however, many details of the minute structure which arc of much interest, and which must be further described. The first cells of Erythrocladia are much less angular and much more oval in shape than those of the host. They divide similarly into sets of four, but they soon lose their regular shape, as they intrude into the thallus of the Porphyra and become most irregular in form, becoming linear, angular, pyriform, and indeed too varied for general description. They average perhaps 10 mmm.—25 mmm. long and 10 mmm.—15 mmm. in breadth, but may be much larger or smaller. They are approximately square to rectangular in section, but often quite
irregular and up to 25 mmm. deep, and the total thickness of the shall us is less than that of the Porphyra, being only 45 mmm.—55 mmm. The breadth of the gelatine between two adjacent cells in the earlier stages is greater than that in the case of the Porphyra, and equal to 5 mmm. The interest in them lies mostly, however, in certain processes and structures they display, which may be termed. (a) invagination (b) cell clustering, and (c) arborescence. (a) Invagination may be seen in a plant of a few mm. in length. Many of the cells become incurved at the base, and the opposed cell-wall of the adjacent cell becomes convex. Then the convex cell puts out one, two, three or even four rhizine-like processes. These processes may divide di- or even tri-chotomously, and then penetrate the wall of a neighbouring cell; or a concave and convex cell may become appressed and unite, with disappearance of the intervening cell-wall. In this way, cells may be linked together in any part of the thallus where Erythrocladia occurs. Frequently the invaginating cells may be found in a circle, from which they radiate out in all directions (Fig. 19). (b) Cell clustering.—Frequently a group of cells orient themselves round a central cell, link up with it and form a central disc 300 mmm. and upwards in diameter with threads of linked up cells, branching out from it in all directions (Fig. 20). (c) Arborescence.—A single cell may send out from one end two three or even four processes, and so link itself up with, several other cells, these in turn invaginating with neighbouring cells form a branched tree-like growth 300 mmm.—500 mmm. or more in length. Such a growth may be termed an arborescence (Fig. 21). I have never seen a cell emitting processes otherwise than from one end, but there is immense variety in the structures that may be formed. In some cases one may have discs or cell-clusters formed without arborescence. These clusters may often be found running roughly parallel with each other in any part of the frond. They usually contain 10—12 cells, more or less completely amalgamated and forming a little richly-coloured tubercular mass projecting from the frond. In other cases the invaginating cells form circular patches without definite arborescence, producing rather a network, enclosing in many cases larger cells, which are perhaps isolated Porphyra cells. Similarly also circular patches of cells-may invaginate without showing either arborescence or cell-clustering, or one may have a series of arborescences radiating out from a centre, but not connected with, each other or with that centre. This, of course, occurs also in Erythrocladia subintegra Rosenvinge, with which our plant seems to be allied. In other cases one may find a large cell-cluster connected up with arborescences, which have subsequently decayed and left the cluster surrounded only by a few isolated cells in the gelatine. The variety of forms assumed is remarkable, and it is impossible to describe them all. If the colourless process put forth, does not meet another cell, it may often expand into a colourless sphere 3—5 mmm. in diameter,
or assume the shape of a wine-glass. This slowly colours until it has the appearance of a stalked cell. The description given is for Erythrocladia as it occurs in Porphyra umbilicalis var. Novae Zelandiae. A similar or perhaps the same Erythrocladia as already noted occurs in P. columbina, but here it seems unable to hold its own. Dead patches of cells, presumably those of Erythrocladia, may often be found in perforations in the thallus of P. columbina, and though P. columbina seems usually to be infected with Erythrocladia, particularly at the base, I have not yet found any large patches of Erythrocladia in this species. In the literature available to me, I have been able to find very little comparable to the invagination process and arborescence. The species of Erythrocladia described by Rosenvinge have obviously arborescences similar to those of this species; but he makes no mention of invagination. J. Agardh, however (1899), p. 149 et seq., observed a similar though less well-developed case of this latter phenomenon in Porphyra nerocystis Anderson; and in consequence of his observations constructed the new genus Pyropia, but this genus was not accepted by Hus. (1901), p. 210; nor by Wille or de Toni (1900), p. 18. Why it was rejected by them I do not know. Though Hus refers to J. Agardh's paper in his bibliography, he does not mention it in his text. Agardh describes his plant under the name Pyropia Californica; and I extract a short passage from his description loc. cit. p. 151, et p. 152. Ex singulis cellulis frondis interioribus, adparenter sua propria membrana cinctis, endochroma expansum vidi in appendicem rostratum, et formam ipsius endochromatis modo offerre unam partem obovatam et conspicue crassiorem, alteramque excurrentem in appendicem plus minus rostriformem; adparatum rostriformem expansum vidi (intra membranam frondis exteriorem) supra partem obovatum proximae cellulae; dum eodem modo partem obovatam intrudentis cellulae (adhuc obtusam) vidi conformi appendicula ab alia cellula proxime vicina proveniente depressam…. Si unaquaque cellula ex uno apice expanditur in appendiculam, eandem cum alia cellula conjugentem; supra alteram vero suam partem incrassatum recipiat consimilem appendiculam, ab alia cellula emissam, facilius, pateat totam structuram hoc modo arctius in formam frondis definitam contineri. Now I have neither specimens of Porphyra nerocystis, nor of the species of Erythrocladia described by Rosenvinge, nor of all the literature necessary, so I cannot pursue this matter further, but it would seem probable that Agardh has found in Porphyra nereocystis (Pyropia) phenomena similar to those that occur in Erythrocladia insignis. Either the Porphyra contains a parasitic species, or else his genus Pyropia may be found on further investigation to stand, or we must expand our definition of the genus Porphyra. It is probable of course that in the case of our New Zealand Porphyras one thallus contains many individuals of Erythrocladia, but it is at present quite impossible to distinguish between one individual and another. Reproduction.—In the arborescences occur cells bearing all the appearance of gonidia as described for the genera Erythrotrichia,
Erythrocladia and Porphyroyopsis by Rosenvinge. These are cut off by a slightly curved cell-wall from the side or end of the cell, or more rarely from solitary cells in the neighbourhood of invaginated areas. It is possibly these gonidia which, scattered throughout the plant, give rise to new individuals in the Porphyra. thallus. Sexual Reproduction.—Densely packed cystocarps (?) occur without vegetative cells, towards the edges of the frond, two or three centimetres deep, divided into two and four without any division parallel to the surface of the frond (Fig. 26). Thus the total numbed of carpospores is only four. Outside these are antheridia divided into four or rarely eight surface dvisions and arranged in four tiers, thus giving sixteen, rarely thirty-two spermatia. The antheridia are colourless, but the red cystocarpic area fades out imperceptibly into the antheridial area. The cystocarps are 10 mmm.—15 mmm. across. The antheridia are 8 mmm.—10 mmm. across and 10 mmm.—12 mmm. in length. Localities: See P. umbilicalis var. Novae Zelandiae. Chief References to Literature. Agardh, J. G. (1877).—De Algis Novae Zelandiae Marinis (Lunds Univers. Aarskrift T. 14) Lund. —— (1882).—Till Algernes Systematik nya Bidrag iii, 6 Ulvaceae (Lunds Univers. Aarskrift T. 19) Lund. —— (1889).—Analecta Algologica Cont. 5 (Act. Reg. Soc. Physiogr. T. 10) Lund. De Toni, J. B. e Forti A. (1923).—Alghe di Australia, Tasmania e Nuova Zelanda, Venezia. De Toni, J. B. (1924).—Sylloge Algarum Vol. 6, Padua. Engler, A., und Prantl K. (1897).—Die naturlichen Pflanzenfamilien Teil 1, Abtallnng 2. Leipzig. Hooker, J. D. (1844-1847).—Flora Antarctica Vols. 1-2 London (The seaweeds are by W. H. Harvey). ——(1853-1855).—Florae Novae Zelandiae, Vols. 1-2. (The seaweeds are by W. H. Harvey). ——(1867).—Handbook of the New Zealand Flora. (The seaweeds are by W. H. Harvey.) Hus, H. T. A. (1902).—An account of the species of Porphyra found on the Pacific Coast of North America. Proceedings of the California Academy of Sciences. Third Series. Botany Vol. 11, No. 6. San Francisco. Laing, R. M. 1899.—Revised List of New Zealand Seaweeds, Part I. (Trans. N.Z. Inst. Vol, 33, pp. 65-70) Wellington. Lainq, R. M. 1902.—Revised List of New Zealand Seaweeds, Part II. (Trans. N.Z. Inst., Vol. 34, pp. 327-359) Wellington. —— 1926.—A Reference List of New Zealand Marine. Algae (Trans. N.Z. Inst. Vol. 57, pp. 126-185) Wellington. Laing, R. M. (1909).—The Marine Algae of the Sub-antarctic Islands of New Zealand, in Chilton, Sub-antarctic Islands of New Zealand, Vol. 2, pp. 503-527. Wellington. Le Jolis A. (3864).—Liste des algues marines de Cherbourg. Memoires de la Société impériale des sciences Naurelles de Cherbourg T. 10. (The Porphyreae in this volume are chiefly described by G. Thuret). Mostagne, C. 1845.—Plantes cellulaires du voyage au Pole sud but les corvettes I'Astrolabe et la Zelée sous le comm an dement de M. J. Dumont D'Urville, Paris. (Montague Prodr. Phyc. Antarct, is not available in New Zealand.) Olimanns, Dr. P. (1922).—Morphologie und Biologie der Algen. Jena. Rosenvinge, L. Kolderup (1909).—The Marine Algae of Denmark, Part I, Introduction Rhodophyceae. (Bangiales and Nemalionales.)
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Transactions and Proceedings of the Royal Society of New Zealand, Volume 59, 1928, Page 33
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13,770New Zealand Bangiales (Bangia, Porphyra, Erythrotrichia and (?) Brythrocladia). Transactions and Proceedings of the Royal Society of New Zealand, Volume 59, 1928, Page 33
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