PNEOPHYLLUM-AMPLEXIFRONS (HARVEY) COMB-NOV A MASTOPHOROID CRUSTOSE CORALLINE RED ALGAL EPIPHYTE FROM NATAL, SOUTH-AFRICA

Pneophyllum amplexifrons (Harvey) comb. nov. is an epiphytic crustose coralline alga (Rhodophyta, Corallinaceae) of the subfamily Mastophoro ideae. It occurs commonly in northern Natal, South Africa and is parti cularly abundant on intertidal populations of the seagrass Thalassoden dron ciliatum (Forsskal) den Hartog. It agrees well with the type spec imen of Melobesia amplexifrons Harvey. A germination disc with 8 centr al cells is present, as usually seen in Pneophyllum. The roof of the t etrasporangial conceptacle forms from filaments surrounding and filame nts interspersed among sporangial initials. A pore canal lined with nu merous small cells confirms that the species pertains to the mastophor oid genus Pneophyllum. Two diagnostic features of P. amplexifrons are humps of uncalcified filaments at the thallus surface and tapered pore canals in the tetrasporangial conceptacles, lined with small, upward- pointing, non-protruding filaments. Comparison with syntypes of Lithop hyllum pseudolichenoides Heydrich shows this species to be conspecific and it is subsumed in Pneophyllum amplexifrons.