DISTRIBUTION OF SEAWEED FLORAS IN THE SOUTHERN-OCEAN

An earlier phytogeographical analysis of the marine algal floras of th e southern oceans using Detrended Correspondence Analysis enabled the recognition of floristic groupings. In the present analysis attention is focused on the floras of islands or coastlines (21 sites) lying wit hin the Antarctic/sub-Antarctic group. The original database has been amended by the addition of new records from Macquarie Island and South Georgia, addition of records from Terra Nova Bay on Antarctica, and a ccount taken of subsequent taxonomic changes. The main axis of variati on in the ordination analysis of 480 species indicates a general north -south trend rather than a sharp discontinuity between the floras of t he Antarctic and sub-Antarctic regions. Floristic provinces are not ap parent, thus islands like South Georgia and Macquarie lie comparativel y close in the ordination despite their vast geographical separation. The species-rich floras of Patagonia, Tierra del Fuego and the Falklan ds appear to form a grouping. The relatively homogeneous distribution of species in the sub-Antarctic region is attributed in part to disper sal by the eastward-moving West Wind Drift.