Algae associated with mangroves in southern African estuaries. I. Rhodophyceae

Macroalgae associated with 19 mangrove estuaries from Kosi estuary to the Nahoon River have been studied. Twelve taxa of the Class Rhodophyceae are described with information on the nature of the substrata for settlement and the seasonal occurrence of fertile plants. Bostrychia moritziana (Sonder) J. Ag., B. radicans (Mont.) Mont. and Caloglossa leprieurii (Mont.) J. Ag. form the persistent components of the mangrove bostrychietum. Bostrychia tenella (Vahl) J. Ag., B. tangatensis Post and B. scorpioides (Gmelin) Mont. have restricted distributions. Polysiphonia subtilissima Mont. and Gelidium spp. are more common associates than Murrayella periclados Schm. and Catenella nipae Zanardini. A freshwater alga is also an associate of the bostrychietum. The findings are discussed and compared with mangrove bostrychieta from other countries, particularly Australia. Makroalge wat met negentien manglietgemeenskappe in riviermonde vanaf Kosiriviermond tot by die Nahoonrivier geassosieer word, is bestudeer. Twaalf taksons van die klas Rhodophyceae word beskryf aan die hand van inligting oor die aard van die vashegtingsubstrate en die seisoenale voorkoms van fertiele plante. Bostrychia moritziana (Sonder) J. Ag., B. radicans (Mont.) Mont. en Caloglossa leprieurii (Mont.) J. Ag. vorm die blywende komponente van die mangliet-bostrychietum. Bostrychia tenella (Vahl) J. Ag., B. tangatensis Post en B. scorpioides (Gmelin) Mont. het ’n beperkte verspreiding. Polysiphonia subtilissima Mont. en Gelidium-spp word meer algemeen geassosieer as Murrayella periclados Schm. en Catenella nipae Zanardini. ’n Varswateralg word ook met die bostrychietum geassosieer. Die bevindings word bespreek en vergelyk met mangliet-bostrychietums van ander lande, Australië in besonder.