A cladistic analysis of southern African subgenus Lapeirousia, one of two subgenera of the exclusively African genus Lapeirousia, yielded four equally parsimonious trees, one of which is identical with the strict consensus tree. Characters used in the analysis included growth form, corm morphology, a range of floral characters, and capsule and seed features, not before known to vary significantly in this genus. The analysis suggested some surprising evolutionary changes. Notable among these is an apparent reversal of perianth tube length from extremely long to short, a shift corresponding to a change from pollination by long-tongued flies and sphinx moths to pollination by bees and noctuid moths. Another unusual change is a shift in floral organization from zygomorphy to actinomorphy correlated with an acaulescent growth form. The reconstructed phylogeny is used here to assess character evolution and patterns of speciation by comparison of species in terminal clades in the cladograms. The resulting comparisons suggest that speciation in the subgenus is either allopatric or the result of microgeographic differentiation and ecological diversification stimulated by edaphic diversity. Despite the variety of floral forms and pollination syndromes in the subgenus there is no evidence of sympatric or pollinator-driven speciation. Prepollination reproductive isolation appears to be achieved by shifts in pollination syndromes between sphinx moths, two guilds of long-tongued flies, and bees. The remarkable floral divergence that has resulted appears to be a consequence of selection for repeated entry into preexisting pollination guilds. The most important of these pollination guilds are two long-tongued fly guilds in which either Prosoeca (Nemestrinidae) or Moegistorhynchus (Nemestrinidae) and Philoliche (Tabanidae) are pollinators. These two guilds are also likely to have been important in promoting speciation in other genera and families in the southern African flora.