Taxonomic studies of the genus Gracilaria (Gracilariales, Rhodophyta) from Australia

Abstract

The taxonomic history of the genus Gracilaria in Australia is reviewed, and nine species are described and illustrated in detail. Two (G. comosa and G. stipitata) are newly described, and the new name G. cliftonii is proposed for the species previously known as G. furcellata Harvey [non G. furcellata (Montagne) Zanardini = Sarconema filiforme (Sonder) Kylin]. New records and observations are given for four species [G. harveyana J.Agardh, G. preissiana (Sonder) Womersley, G. salicornia (C.Agardh) Dawson, and G. urvillei (Montagne) Abbott in Abbott, Zhang & Xia], and two species [G. blodgettii Harvey and G. cf. vieillardii Silva in Silva, Menez & Moe] are added to the Australian flora. An additional seven or eight species that are incompletely known also occur on the continent and are briefly discussed but not illustrated. For nomenclatural and anatomical reasons we propose that G. spinulosa (Okamura) Chang & Xia forma srilankia Chang & Xia, based on G. purpurascens Harvey ex J. Agardh [non G. purpurascens (Hudson) Greville = Cystoclonium purpurascens (Hudson) Kutzing] and not yet recorded from Australia, be elevated to species status as G. srilankia (Chang & Xia) comb. nov. We propose that Gracilaria harveyana J. Agardh 1885 be conserved against Polyides flagelliformis Sonder 1845, which Professor H.B.S. Womersley has determined is an obscure but earlier name for this well-known Western Australian species.