Because of the fact that no marine macroalgal flora exist for the Kenyan coast, nor for the whole Indian Ocean, a flora of the green algae (Chlorophyta) is now in preparation. Therefore material has been gathered annually during the period 1985-1992 in as many habitats as possible. The field work is still going on at the moment. The different groups of seaweeds are analyzed, drawn and described consecutively; identification keys to the genera and species as well as descriptions of biotopes are given; they are the basis for ulterior ecological field work. The Caulerpales were studied as a first group because they are very important in any tropical marine biotope. The genus Caulerpa was published by COPPEJANS & BEECKMAN (1989, 1990). In the thesis of VERELLEN (1990) the remaining genera of the Caulerpales are described: Avrainvillea, Chlorodesmis, Halimeda and Udotea. The Siphonocladales with the genera Anadyomene, Microdictyon, Bøergesenia, Boodlea, Chamaedoris, Struvea, Siphonocladus, Dictyosphaeria, Ernodesmis, Valonia, Ventricaria, Valoniopsis are treated in the thesis of VERSTRAETE (1993). In this thesis the Cladophorales with the genera Chaetomorpha, Cladophora, Rhizoclonium and Cladophoropsis are studied. The genus Chaetomorpha is represented by 7 species: C. aerea, C. brachygona, C. capillaris var. crispa, C. clavata, C. crassa, C. gracilis and C. spiralis. The genus Cladophora is represented by the following 7 species: C. (cfr.) albida), C. coelothrix, C. fascicularis, C. Mauritiana, C. patentiramea f. longiarticulata, C. saviniana and C. sibogae. There also are two entities which cannot be assigned to a known described species. The genus Rhizoclonium is represented by only 2 species, namely R. africanum and R. grande. The genus Cladophoropsis which, according to some authors, belongs to the Siphonocladales because of the different way of septa formation, includes 4 species: C. macromeres, C. sundanensis, C. vaucheriaeformis and C. zollingeri. There also is another entity with a striking large diameter which has never been described before. This could be a new species. Of course it cannot be excluded that supplementary species or genera will be found in the future, because of the punctual distribution of some species of seaweeds on the one side, and because of the inaccessibility of the northern half of the Kenyan coast on the other side. Moreover, the infralitoral of the seaward side of the coral reef still remains almost unstudied because of organizational problems (boat or diving equipment not being available during our research periods). Compared to the results of SARTONI (1992), who only described 3 species of Chaetomorpha and 3 species of Cladophoropsis for the Somalian coast, the Cladophorales flora of the Kenyan coast seems to be very rich. The Somalian algal flora also seems to be different as it contains 2 species which are not found in Kenya, namely Chaetomorpha antennina and Cladophoropsis herpestica. JAASUND (1976) mentions 2 species of Chaetomorpha and 2 species of Cladophoropsis for the Tanzanian coast, of which Chaetomorpha indica is not mentioned for Kenya. BØRGESEN (1940, 1946, 1948) lists 7 Chaetomorpha species for Mauritius: C. aerea, C. antennina, C. gracilis, C. indica, C. linoides, C. linum, C. natalensis and 4 Cladophoropsis species: C. limicola, C. sundanensis, C. vaucheriaeformis en C. zollingeri. Rhizoclonium africanum as well as R. grande occur as well along the Kenyan and Somalian coast (SARTONI 1992), while JAASUND (1976) only mentions R. grande for Tanzania. BØRGESEN (1940, 1946, 1948, 1952) reports 3 species for Mauritius: Rhizoclonium grande, R. kerneri and R. kochianum. Worldwide, many species of Cladophora are described and mentioned, especially by VAN DEN HOEK (1963, for Europe) and VAN DEN HOEK (1982, for the North Atlantic Ocean). Compared with this the number of Cladophora species, found along the Kenyan coast is rather restricted, though higher than the reports of SARTONI (1992) for the Somalian coast and those of JAASUND (1976) for the Tanzanian coast. In these areas there are only 5 species described. JAASUND (1976) describes the same species as found for Kenya and SARTONI (1992) also mentions C. ordinate and C. vagabunda (syn.: C. fascicularis and C. mauritiana) which are not mentioned for Kenya. BØRGESEN (1940, 1946, 1948, 1952) reports on the following species from Mauritius: C. boodleoides, C. cristata, C. echinus, C. fascicularis, C. fuscescens, C. inserta, C. intertexta, C. mauritiana, C. patentiramea f. longiarticulata, C. prolifera, C. rupestris, C. saviniana and C. timorensis. With this work we hope to contribute to the preparation of a flora of the green algae (Chlorophyta) along the Kenyan coast (or the East African) coast. Such an algal flora is indispensable as a basis for any ecological research. |
