Southern Australian species of Melobesia (Corallinaceae, Rhodophyta)

Abstract

The genus Melobesia (Corallinaceae, Rhodophyta) is represented in southern Australia by two species: M. membranacea (Esper) Lamouroux, which occurs throughout the world, and M. rosanoffii (Foslie) Lemoine, known only from the study region. Detailed studies of the type specimens of both species are provided, together with taxonomic, morphological and anatomical accounts of southern Australian populations. An assessment of diagnostic and ancillary characters has shown that the mode of tetrasporangial and carposporangial conceptacle development, thickness and anatomy of male conceptacle roofs, and thickness and anatomy of carposporangial conceptacle roofs can be used to delimit the species. None of the diagnostic characters used to separate the two southern Australian species has been used previously for species delimitation within the genus. Twelve additional entities reported from southern Australia under the name Melobesia have been excluded from the genus, and one additional species (M. darwinii Harvey) remains a species inquirendum. Historical background data and a key to southern Australian species are also included.