The concept of life form is one of the cornerstones in ecology. Insight into the relationship between life form and climate leads to the classification of biomes, which is largely based on the dominance of plant life forms. The BIOTA Observatories along the southern African transect covered six different biomes in southern Africa. After nine years of observation, data from these Observatories were analysed for patterns of relative cover and richness of the five basic life forms of Raunkiaer as well as extended life forms along the major climatic gradient. Our findings partly confirmed, and to some extent modified existing biome classifications for southern Africa. Furthermore, the relationship between life form composition and precipitation along the transect was analysed in a direct gradient analysis using fuzzy set ordination. The gradient analysis revealed species richness per life form as a suitable proxy to quantify life form occurrence in relation to annual rainfall. Finally, it was shown that not all proposed biomes can be separated clearly regarding richness or relative cover of life forms.