Three new species of parasitic red algae (Rhodophyta) from Australia:Holmsella australissp. nov.,Meridiocolax bracteatasp. nov. andTrichidium pedicellatumgen. et sp. nov.

Abstract

One genus and 3 spp. of parasitic reed algae are described as new from Australia. H. australis sp. nov. (Choreocolacaceae, Cryptonemiales) is found on Gracilaria furcellata Harvey in 2 shallow bays of Victoria and differs from the only other species of the genus [H. pachyderma (Reinsch) Sturch] in size and anatomical details, primarily the morphology of vegetative cells and the positions of carpogonial branches. M. bracteata sp. nov. (Rhodomelaceae, Ceramiales) is found on Polysiphonia sparsa (Setchell) Hollenberg at Lord Howe Island, 600 km off the coast of New South Wales, and differs from the type species of the genus (M. narciussus Morrill) in having tetrasporangia rather than bisporangia and by the consistent association of a sterile trichoblast "bract" with each spermatangial head. TRICHIDIUM pedicellatum gen. et sp. nov. (Rhodomelaceae, Ceramiales) grows on Lophocladia harveyi (Kutz.) Schmitz at Port Denison in Western Australia and is characterized by its trichoblastic tetrasporangial stichidia and the prominent scar cells left by deciduous trichoblasts. Its procarp, which includes a single 3-4 celled sterile group, shows affinities to the tribe Lophothalieae, in which the genus is provisionally placed.