Central Namib endemics have probably descended from old evolutionary lines in contrast to those in the southern Namib. Different selective forces are therefore likely to be driving evolution in different parts of the Namib Desert. Although leaf-succulents are over-represented among both central Namib and southern Namib endemics, leaf-succulents in the central Namib are likely to be a result of former environmental conditions (i.e. winter rainfall) and/or the influence of fog, in contrast to the southern Namib where phylogenetics play a more important role. Species-specific responses are indicated among the Namib endemics, as the influence of fog seems to be important for some, and substrate conditions for others. These need to be taken into account when predictions are made regarding broad-scale biogeographic patterns and when modelling the effect of climate change. Keywords: arid lands, biogeography, climate change, evolution, growth forms, southern Africa.