TAXONOMY OF EUCHEUMATOIDAE IN CHINA
Kuang Mei,Zeng Chengkui,Xia Bangmei(Institute of Oceanology,Chinese Academy of Sciences)
Betaphycus Doty, Eucheuma J. Agardh and Kappaphycus Doty are three important economic red genera that distribute in tropical and subtropical areas, belong to Eucheumatoidae,Solieriaceae,Gigartinales and Rhodophyta,and have been used as raw materials for the production of carrageenan.Samples of the three genera, collected and kept for many years, or received from foreign countries,are deposited in the Herbarium of the Institute of Oceanology, Chinese Academy of Sciences. The characters of gross morphology, vegetative anatomy, especially the reproductive organs of thalli, are used for taxonomy of the three genera. There are altogether 1 species of Betaphycus, B. gelatinum(EspeT.)Doty;5 species of Eucheuma, E. arnoldii Weber-van Bosse,E. denticulatum(N. L. Burman)Collins et Hervey,E. perplexum Doty, E. serra J. Agardh,E. xishaensis sp. nov. ; and 3 species of Kappaphycus, K. alvarezii (Doty) Doty, K. cottonii (Weber-van Bosse) Doty, K. striatum (Schmitz) Doty. Among these, E. xishaensis sp. nov. is a new species, Betaphycus and Kappaphycus are newly recorded genera in China respectively.Diagnosis of the new speciesEucheuma xishaensis sp. nov. (text-fig. 6;pl. V:2)Thalli cylindracei, irregulariter ramificantis; primariae cellulae medullosae pseudoparenchy matae saepe isodiametricae et ferentes thylles procurrentes in spatia intercellulosa ;cystocarpia hemisphaerice, strato speeiali cellularum inter pericarpium et gonimoblastum.Thallus erect cylindrical, irregularly branching, arising from a compound holdfast. Branches generally 1cm in dia. from base to apex. There are two kinds of branches, one is quite smooth,the under surface and both margins of the other are densely covered with long,thin branchlets and small wart-like protuberances dark purplish red in color.Thallus in transverse section consisting of 3 layers of cortical cells, pigmented, ovoid, 13μm×7μm in dimensions ; toward the center; the pseudoparenchymatouscells of the medulla gradually enlarging,small and large cells mixed in the cylindrical axes.Thallus of cystocarps thick, having wart-like protuberances. Cystocarps on the under surface of the thallus,at the connections of the protuberances and the main branches; protuberances hemi-spherical, often qpiculate. Cystocarps 720μm × 614μm in dimensions; gonimoblast arising from a large fusion cell; carpospores about 33μm×17μm in dimensions, surrounded by pericarp. The space between the inner surface of the pericarp and the clusters of the carpospores is the space full of gel. Tetrasporangia and spermatangia unknown.Holotype:AST 80-1447(pl. V right) ,cystocarpic,growing on coral,Quanfu Island, Xisha Islands ,China ,May 3 ,1980 ;leg. Zhang Derui.Isotype:From the same collection as holotype, AST80-1447A(pl. V: 2 left).