Begonia is a large pantropical genus of herbs, shrubs and lianas. A wide variety of dispersal mechanisms have been recorded from the genus. The majority of the c. 600 Asiatic species of the genus have dehiscent, winged, capsular fruits and appear to be adapted to either wind or rain-splash seed dispersal. However, c. 25 Asiatic species have indehiscent, baccate fruits that usually lack wings and appear to be adapted for animal dispersal. This morphologically diverse group of fleshy-fruited species has traditionally been classified in the section Sphenanthera, which is distinguished from other Asiatic Begonia sections on this character alone. In order to determine whether the section Sphenanthera represents a monophyletic species group, nuclear, chloroplast and mitochondria markers were analysed cladistically for a representative sample of species from section Sphenanthera and from 11 of the 17 other Asiatic sections. Begonia species from Africa were used as outgroups in these analyses. Begonia section Sphenanthera was found to be polyphyletic, indicating that baccate fruits have evolved multiple times within Asia. The evolutionary significance of animal dispersed and rain-splash dispersed seed are discussed in the light of these analyses, and changes to the sectional classification of these fleshy-fruited Asiatic species are proposed.

Key words: Asia, Begonia, biogeography, classification, section Sphenanthera, seed dispersal