NOTES ON INDIAN RED ALG^—I

B y M . s . B alakrishnan University Botany Laboratory, Madras-5

(With 21 Text-Figurcs)

(Received for publication on December 16, 1957)

D u r in g a special study of Indian , the writer came across two interesting epiphytic red algae belonging to the family Ceramiaceae. These are described in the present paper.

Gymnothamnion elegans (Schousboe) J. Agardh This alga was collected growing on Corynomorpha pnsmatica (Ag.) J. Ag. from Cape Comorin, South India. It forms small bright red tufts 1-Hcm. high on the basal portions of the host. The pro­ strate creeping portion consists of branched filaments fixed to the host by means of multicellular rhizoids at intervals (Text-Fig. 2). The cells of the creeping filaments are cylindrical, 10-12 x 30-45/x and thick walled. The cells giving rise to rhizoids are much shorter than the others and these also give rise to erect branches oiT the upper side (Text-Fig. 1). The erect branches are 10-15 mm. in height, plumose, usually simple, but occasionally pinnately branched; cells of the erect branches are up to 25 ^ long and 10-15/x wide. Generally they are slightly broader at the top (Text-Fig. 3). Each cell bears at the top a pair of opposite branchlets (pinnules) six to eight cells long, the cells measuring 10-12 n x 10-18 ft. The branchlets are distichously arranged and except in the youngest parts, almost of uniform length so that the erect branches are characteristically plumose and oblong or linear lanceolate in outline (Text-Fig. 1). Production of the branchlets starts right from the base (Text-Fig. 1); it is only in the older stages that the lower parts of the erect branches become bare, evidently due to the dropping off of older branchlets. Both the prostrate and erect filaments are totally ecorticate. The tetrasporangia are borne terminally on the branchlets. They are ellipsoid to ovate, 25-30/x wide and 3 0 - ^ /x long. The tetraspores are usually pyramidally arranged (Text-Fig. 3), but cruciate arrange­ ment is also frequently met with (Text-Fig. 4) (see also Bornet and Thuret, 1876, Plate X, Fig. 2). • The alga is dioecious. Spermatangia are borne in clusters on short multicellular accessory branches at the tips of the branchlets (Text- Figs. 7, 8). Each cell of these lateral branches functions as a sper- matangial mother cell and bears two to three spermatangia at the top, (Text-Fig. 11) (see also Bornet and Thuret, 1876, Plate X, Fig. 3). Text-Fios. 1-4. elegans. Fig. 1. Part of plant showing general habit and branching. Fig. 2. Part of creeping filament to show branching and rhizoids. Figs. 3-4. Portions of erect branches to show tetrasporangia. Development o f the procarp up to feriilizaiion The procarps are borne on the branchlets near ihe tips, usually on the subterminal cell. The sequence of development is as follows: The subterminal cell first cuts off a pericentral cell on the abaxial side. (Text-Fig. 5), and a little Jater, one more pericentral cell is cut off aterally (Text-Fig. 6, pc). The abaxial pericentral cell divideis further Tbxt-Fiqs. 5-12. Gymnothanwion elegans. Fig. 5. First stage in the for­ mation of the procarp. Fig. 6. A later stage showing the carpogonial branch initiated and the lateral pericentral cell formed. Figs. 7-8. Tips of branchlcts from a male plant showing early stages in the formation of the spermatangia. Fig. 9. Young procarp showing the four

Text-Figs 13-14. Gymnothamnion elegans. Figs. 13-14. Young and old cystocarps showing structure and the persistent lateral sterile branch with its terminal hair, {sc, supporting cell.) * carpospores are quite large, bright red, and measure 15-20p in dia­ meter. After the liberation of carpospores, the empty outer sheath persists as a transparent sac for sometime (Text-Fig. 14). Vestiges of the carpogonial branch can be made out even in the ripe cystocarps. The lateral sterile branch with its terminal hair always persists and is prominently seen in the fructifications (Text-Figs. 10, 13, 14). ■

Bornet and Thuret (1876) have given an account of the asexual and sexual reproduction of this alga. The present account agrees in general with their observations. In this paper the writer has given details of early post-fertilization development also. The details of early post-fertilization development are in agreement with what has been described for the related genera Ptilota (Kylin, 1923) and Plumaria (Suneson, 1938; Drew, 1939). In these two genera, the carpogonium after tertilization divides into two cells, the lower of which functions as the connecting cell (sporogenous cell) and fuses with the auxiliary cell. The present observations indicate that the Indian Gymnothamnion differs from these and shows similarity to genera like Antithanmion in the division of the fertilized carpogonium into three cells, the lowermost of which establishes connection with the auxi­ liary cell. Callithamnion elegans Schousboe ex C. Agardh (1828, p. 162) was transferred to Plumaria Schmitz {non Plumaria Stackhouse) by Schmitz in 1889 as P. schousboei (Bornet) Schmitz. J. Agardh (1892), however, segregated it as a new genus, Gymnothamnion [type species, G. elegans (Schousboe) J. Ag.]. Gymnothamnion is distinguished from Plumaria Schmitz by its small size, absence of cortication and simple unbranched nature of the branchlets. The present study indicates that the formation of only one lateral pericentral cell in the fertile segment and the division of the fertilized carpogonium into three parts may serve as additional distinguishing features. Collins and Hervey (1917) added two more species to Gymno­ thamnion, G. sericeum (Harvey) Collins et Hervey and G. bipinnatum Collins et Hervey. Feldmann-Mazoyer (1940, p. 353) included G. bipinnatum as well as Plumaria ramosa Yamada and Tanaka (1934) in G. elegans. She, however, was not certain whether G. sericeum and G. elegans could be kept in the same genus. Later, she (1950, p. 310) kept only G. elegans in the genus, transferring G. sericeum to Plumaria Schmitz as a synonym of Plumaria elegans (Bonnem.) Schmitz. The genus Gymnothamnion is, thus, monotypic (see Kylin, 1956, p. 389; see also Silva, 1952, p. 288). C. elegans is known from the Mediterranean and adjoining parts of the Atlantic Ocean, Bermuda, the Canary Islands, Formosa (Japan), the Pacific coast of Mexico, Clarion Island in the Revillagagido Archipelago, Isabella Island on the Equador coast and New Zealand (Setchell and Gardner, 1930; Schiffner, 1931; Feldmann-Mazoyer, 1940, 1950; Taylor, 1945; Dawson, 1953; Kylin. 1956). It is recorded here for the first time from India. Antithamnion floccosum (Miill.) Kleen. A single small female plant of this alga was found growing on a specimen of Halymenia floresia (Clem.) Ag. collected from Tuticorin by Prof. M. O. P. Iyengar who kindly passed on the material to the writer. The plant was about 6 cm. high and showed the lax branching, with basal portions almost bare, characteristic of the species. The branching was subalternate pinnate and the branchlets (pinnules) incurved, arising from the upper portions of the articulations. The branchlets were opposite and distichous, simple, often with unequal development, the branchlet on the inner side reduced to one or two cells. The tips of the branches and branchlets were somewhat pointed in the older portions and rounded in the younger portions. Gland cells were not seen. The material showed stages in procarp development and also early post-fertilization stages, though lacking ripe cystocarps. The procarps occur near the growing tips, the basal cell of a normal fully developed branchlet serving as the supporting cell of the carpogonial branch (Text-Figs. 15, 17). The carpogonial branch is four-celled; the ter­ minal cell is the carpogonium and has a well-developed trichogyne (Text-Fig. 19). 20 21 Text-Fios. 15-21. Aniithamnion floccosum. Figs. 15-17. Stages in the development of the procarp. Fig. 18. Procarp after fertilization showing division of the carpogonium into two cells and the cutting off of the auxiliary cell from the supporting cell. Fig. 19. Procarp prior to fertilization. Fig. 20. Procarp after fertilization showing the connecting cell. Fig. 2i. Still latrr state, showing irjtia- tion of gonimoblast. (aux, auxiliary cell; cc, connecting cell; cpg, carpogonium; gon, goniraolobe; sc, supporting cell.) After fertilization, the trichogyne is first cut off; the carpogonium then divides to form an upper smaller and a lower larger cell (Text- Fig. 18, cpg). At about this stage, the supporting cell also cuts off the auxiliary cell on the upper side (Text-Fig. 18, aux). After the formation of the auxiliary cell, the lower derivative of the fertilized carpogonium cuts off a small cell on the under side (Text-Fig. 20, cc.) which functions as a connecting cell between it and the auxiliary cell. After this connection is established, the carpogonial branch starts degenerating. The auxiliary cell next divides into an upper large gonimoblast initial and a lower small foot cell. The gonimoblast initial gives rise to the gonimolobes (Text-Fig. 21, gon). The details of development recorded here agree with what has already been reported for other species of Antithamnion by various workers (Phillips, 1897; Daines, 1913; Kylin, 1923, 1925; Rosenvinge, 1924; Capt, 1930; Westbrook, 1934; Levring, 1941; Segawa, 1949; Chadefaud, 1954). Species of Antithamnion are clearly divisible into two groups, (1) in which the procarp is borne on the basal cell of a fully developed branchlet [A. plumula (Ellis) Thuret, A. occidentale Kylin, A. tenuis- simum (Hauck) Schiffner, A. floccosum (Miill.) Kleen, A. subulatum (Harv.) J. Ag., and A. minutissimum Levring] and (2) in which the fertile branchlet is reduced and is one to three cells long \A. pacificum (Harv.) Kylin and A. spirographidis Schiffner] (see Feldmann-Mazoyer, 1940; Kylin, 1956). Only two other species of Antithamnion appear to have been previously reported from this region, viz., A. plumula (Murray, 1881, p. 5, as CalHthamnion plumula Lyngb.) and A. elegans Berthold (Anand, 1943, p. 22, Figs. 14-15), both records being from Karachi.

S um m ary Gymnothamnion elegans (Schousboe) J. Ag. (Ceramiaceae, Ptilote®) and Antithamnion floccosum (Miill.) Kleen (Ceramiaceje, Crouanieae) are reported for the first time from India. The structure and reproduction of G. elegans is described in detail, especially the development of the procarp before and after fertilization. Points of interest and the of the genus are briefly discussed. Development of the procarp and early post-fertilization stages in A. floccosum are also described. The writer is indebted to Profs. M. O. P. Iyengar and T. S. Sadasivan for encouragement and to Dr. T. V. Desikachary for cri­ tically going through the paper and for helpful suggestions.

R eferences

Agardh, C. a . 1828. Species algarum, 2: Ixxxvi + 189 pp., Gricfswald. Aoardh, J. G. 1892. Analecta algologica. Acta Univ. Lund. : 1-182. Anand, P. L. 1943. Marine alga from Karachi, 2: Rhodophyceaj: ii+ 76 pp., Lahore. ' Boergesen, F. 1930. Marine alg® from the Canary Islands, especially from Teneriffe and Gran Canaria. 3, Rhodophycea, III. Ccramialcs., Biol. Medd. Kbh. 9.‘ 1-158. Bdrnet, B, and T huret, G. 1876. Notes algologiques. 1: xx + 70 pp. Paris. 10 C a pt , L. 1930. Ths msrphology and lifc-history of AntitliamnioK. Publ. Puget SJ. Mar. {biut.) Sla. 7 ; 369-78. CHA.QEFAUQ, M. 1954. Sur la morphologic de quelques Ceramiacte, Rev. algul. N.S. 1: 71-87. C ollin s, F. S. an d H ervey, A. B. 1917. 'I'hc alga; of Bermuda. Proc. Amer. Acad. Art.s Sci. 53: 1-195.

D aines, L. L, 1913. Comparative development of the cystocarps of Aiilillianmion and Phonitis. Univ. Calif. Publ. B ol.4: 283-302.

D a w so n , E. Y. 1953. A summary of rec.enl marine algal investigations, wilh a synopsis of literature, synonymy and distribution of species. Rev. Sue. mex. Hist. nut. 13; 97-197.

D r e w , K. M. 1939. An investigation of Ptumaria elegaii.',- (Bonneni.) Schmilz with reference to triploid plants bearing para sporangia. Aim. Bot. Linul. IS S. 3 : 343-67.

F elum ann-M a zoyer, G. 1940. Reeherches sur U's Ceramiaeees de la AfeJitcrra- neanie uceithntale. Alger, 510 pp. 1950. Sur les quclqucs Ceramiaeees dc Nouvelle Zelande. Bull. Mus. Hist. nat. Paris, ser. 2, 22: 131 41 ; 307-14.

K ylin, H. 1923. Studien iiber die Entwicklungpgcscliichte der Florideen. K. Svcnska Vetensakad Handl. 63: 1-139. ------, 1925. The niirine Red Alg:c in the vicinity of Friday Harbour, Wash. Acta Univ. Lund. 21: 1-87. ------. 1937. Anatomic dor Rhodophyeceii. Handb. PfI-Anat. Abt. H , 6: viii I- 347 pp. ------. 1956. Die Gattungen der Rliodophyceeir. xv I 673 pp., Lund. LnvRiNu, T. 1941. Die Mjeresa/gen der Juan Fernandez liiseln. in C. Skottsbcrg, Natural History o f Juan Fernandez and toaster Island, 2: 601-70.

M urr a y , J. A. 1881. The Plants and Drugs o f Sind: xxxv"h 219 pp., Bombay and London.

P uillihs, R. W. 1897. O.i the development of the cystocarp in Rhodymeniales. Ann. Bit. Lond. 11: 347- 68.

R osenvinoe, L. K.. 1924. The Marine Alg;c of Denmark, Part III, Rhodophyceic, lU. Cjramialcs. K. danske Videmk. Selsk. 1: 287-486.

S ch iffn er , V. 1931. Neue und Bsmerkenswerte Meeresalgen. Hedwigia. 71: 139 205.

S c h m it z , C. J. F. 1889. Systematisch ubersichtder bisher bekannten Gattungen der Florideen. Flora, 72: 435 56.

Seo a w a , s . 1949. The gonimoblast development in Ceramiaceous algie of Japan, I. J. Fae. Agric. Kyushu Univ. 9: 143-47. ’

S etch ell, W. a . 1930. Marine algx of the Revillagagitfo Islands expedition of 1925. Proc. Calif Acad. Sci. h,\9 \ 109-215.

Silv a , P. C. 1952. Nomenclatural conservation in the algae from the point of view of the type method. Univ. Calif. Publ. But. 25: 241-324.

Suneson, S. 1938. Ueber die Entwiekkmgsgeschichte von Pluniarie elegans. K. fysiogn. SSIIsk. Lund Forh. 8 (9).

T a ylor, W. R. 1945. Pacific marine alga; of the Allan Hancock expedition to the Galapagos Islands. Allan Hancock Pacif. Exped. 12: 1-528.

W estbrook, M. A. 1934. Anlitliamnion spiragraphidis Schiffner. J. Bot., Lond 72: 65-68.

Y am ada, Y. a n d T anaka, T. 1934. Throe new Red Alg® from Formosa. Trans, nat. Hist. Soc., Formosa. 24: 342-49.