This study treats the green algae, belonging to the Siphonocladales from the Kenyan coast. This work forms a small part of a global floristic study about the East African algae. Fieldwork has been carried out on a yearly basis since 1985 under the supervision of E. Coppejans; the last field trip at which we participated, took place in September 1992. The collected specimens were conserved either as herbarium specimens and/or pickled in formalin. At the University of Ghent (RUG) these specimens as well as those collected during previous field trips were analyzed, drawn and described in detail. Identification keys were composed (see p. 80). For the Siphonocladales 13 genera were found, containing 18 species. In Kenya most of the genera only contain one species; exceptions are Dictyosphaeria (with 3spp.) and Valonia (with 3 spp.). In our collection the genus Anadyomene only contains the species A. wrightii and A. plicata along the Somalian coast. JAASUND (1976) and BØRGESEN (1940) only noted A. wrightii respectively from Tanzania and Mauritius. Microdictyon agardhianum is the only species in Kenya belonging to this genus. Sartoni (1992) described M. japonicum for the Somalian coast. BØRGESEN (1940, 1954) on the other hand found six species for the coast of Mauritius: M. agardianum, M. krausii, M. montagnei, M. pseudohapteron, M. spongiola, M. sp.. Boergesenia is a monospecific genus with B. forbesii as a single species, which is common for the region. Boodlea composite is the common species for the region. ISAAC (1967) also described B. montagnei for Kenya; Sartoni (1992) noted the latter and B. vanbosseae for the Somalian coast. BØRGESEN described three species for the coast of Mauritius (B. composita, B. elongate, B. contracta). In our material the genus Chamaedoris is represented by C. auriculata. Moorjani (1977) lists also C. delphinii for Kenya. Sartoni (1992) described both species for the Somalian coast. Only the latter was described by JAASUND (1976) for Tanzania. In Mauritius five species are mentioned by BØRGESEN (1940): C. annulata, C. auriculata, C. delphinii, C. orientalis, C. periculum. S. anastomosans is common in the region. Mauritius is the only place in the Indian Ocean where another species is described by BØRGESEN (1940, 1952): S. elegans. Our material contains only S. tropicus of the genus Siphonocladus, this is the first report for Kenya. BØRGESEN (1940, 1946, 1948) found five species (S. delphinii, S. feldmanii, S. perpusillus, S. pusillus, s. tropicus). Pseudostruvea is also a monospecific genus with the species P. siamensis. Sartoni (1992) described it also along the Somalian coast. The genus Dictyosphaeria includes three species: D. cavernosa, D. vanbosseae and D. setchellii. D. intermedia and D. versluysii were also described along the Kenyan coast by Moorjani (1977) and Isaac (1967). JAASUND (1967) and SARTONI (1992) found respectively two species in Tanzania and Somalia (D. cavernosa, D. versluysii). BØRGESEN (1940, 1946, 1952) noted six species for the coast of Mauritius (D. cavernosa, D. intermedia, D. setchellii, D. vanbosseae, D. versluysii, D. australis). Of the genus Ernodermis only E. verticillata was found. In Somalia and Tanzania this genus has not been mentioned. Three species belonging to the genus Valonia were found: V. aegagrophila, V. macrophysa, V. utricularis; V. utricularis was not found in Tanzania by JAASUND (1967). BØRGESEN (1940-1953) noted another two species (V. cladophora, V. confervoides). The genus Ventricaria is monospecific and includes V. ventricosa, which is common for the region. The genus Valoniopsis exclusively includes V. pachynema, which is common for the region except in Mauritius. The representatives of the Siphonocladales from Kenya are very similar to those from Somalia, described by SARTONI (1992) and to Mauritius described by BØRGESEN (1940-1954). Tanzania has a less developed algae vegetation as we notice from the JAASUND fieldflora (1967). It is not out of the question that other genera and species may appear along the Kenyan coast, because only a small part of the coast was sampled (the northern part was not accessible) and other areas were too difficult to reach. Further research is necessary to complete this study and to make a complete flora. |
