Morphology And Taxonomy of the Audouinella Complex (Rhodophyta) in Southern Australia

Abstract

The morphology and taxonomy of the southern Australian representatives of what has been frequentiy referred to as the "Acrochaetium-Rhodochorton" complex of the Rhodophyta have been studied. The type species of both Acrochaetium and Rhodochorton are placed in the genus Audouinella and the group is now referred to as the Audouinella complex. Two genera are recognized in this region: Audouinella (syn. Acrochaetium, Balbiania, Chromastrum, Grania, Rhodochorton), known to reproduce sexually, contains 12 southern Australian species (including A. blumii sp. nov.) and is referred to the Audouinellaceae nom. nov. Colaconema, treated here as a genus comparable with form genera of the Fungi Imperfecti, contains 14 southern Australian form species, all unknown in the sexual state. The generic classification proposals of Feldmann (1962), Kylin (1956), and Papenfuss (1945, 1947) are not supported by this study. Few morphological features of audouinelloid algae are of general systematic value, but pyrenoid numbers, sporangial dimensions, and cell dimensions appear to be the most reliable criteria for systematic purposes. Other features (e.g. fonn of the prostrate system, chromoplast shape, occurrence and position of hairs, spennatangial morphology, and immediate post-fertilization development) show too much variation to be used reliably in species and!or generic separation. Infonnation on the tropical Australian species is briefly summarized.