Morphology of the type and Australian species of Dudresnaya (Dumontiaceae, Rhodophyta)

Abstract

The genus Dudresnaya is reviewed and a key to its 12 species is given. The European type species, D. verticillata (Withering) Le Jolis, and the three species known from Australia (D. australis Setchell, D. hawaiiensis R.K.S. Lee, D. capricornica sp. nov.) are described in detail. Dudresnaya australis and D. verticillata are similar in habit but distinguishable by their internal structure. Dudresnaya hawaiiensis, previously recorded only from the Hawaiian Islands, is now known from several eastern Australian localities and is the most morphologically variable and geographically widespread of all the Dudresnaya species. The newly described species, D. capricornica, is also extremely variable in habit and occurs in both eastern and western Australia.