XVI International Botanical Congess
Presence / absence data for more than 1800 species from sub-Saharan Africa were recorded on a 2.5 x 2.5 degree grid. Both species richness and endemism are very varied across the continent, with several distinct centres of both richness and endemism. While species richness is related to total rainfall and distance from the equator, endemism is strongly related to the distance from the Sahara, and we suggest that expansions and contractions of the Sahara might have been a powerful driving force in shaping the African plant distribution patterns. Distribution data for Australia plant species (Eucalyptus and other genera) were investigated to search for similar evidence of an expanding and contracting central desert region.