Hydrolithon pellire sp. nov., a mastophoroid crustose coralline red algal epiphyte from South Africa

Abstract Hydrolithon pellire sp. nov. (Rhodophyta, Corallinaceae) is a thin, crustose epiphyte that grows mainly on intertidal plants of Gelidium pteridifolium R.E. Norris, Hommersand et Fredericq in Natal and eastern Cape Province, South Africa. It has cell fusions and uniporate tetrasporangial conceptacles characteristic of the subfamily Mastophoroideae. The conceptacle pore is surrounded by enlarged, vertically oriented cells characteristic of the genus Hydrolithon. Hydrolithon pellire appears to have a germination disc of c. 48, small, squarish cells; this type of disc is normally associated with the multiporate genus Melobesia.