BIOGEOGRAPHY AND FLORAL EVOLUTION OF BAOBABS (ADANSONIA, BOMBACACEAE)AS INFERRED FROM MULTIPLE DATA SETS

The phylogeny of baobab trees was analyzed using four data sets: chlor oplast DNA restriction sites, sequences of the chloroplast rpl16 intro n, sequences of the internal transcribed spacer (TTS) region of nuclea r ribosomal DNA, and morphology. We sampled each of the eight species of Adansonia plus three outgroup taxa from tribe Adansonieae. These da ta were analyzed singly and in combination using parsimony. ITS and mo rphology provided the greatest resolution and were largely concordant. The two chloroplast data sets showed concordance with one another but showed significant conflict with ITS and morphology. A possible expla nation for the conflict is genealogical discordance within the Malagas y Longitubae, perhaps due to introgression events. A maximum-likelihoo d analysis of branching times shows that the dispersal between Africa and Australia occurred well after the fragmentation of Gondwana and th erefore involved overwater dispersal. The phylogeny does not permit un ambiguous reconstruction of floral evolution but suggests the plausibl e hypothesis that hawkmoth pollination was ancestral in Adansonia and that there were two parallel switches to pollination by mammals in the genus.