Melastomeae are pantropically distributed and comprise ~550 spp. in the New World, including the 13 spp. of Rhexia in North America, 170 spp. in Africa, 70 in Madagascar, and 50 spp. of Melastoma and Osbeckia in SE Asia and tropical Australia. The monophyly of Melastomeae is strongly supported by combined rbcL, ndhF, and rpl16 cpDNA sequences analyzed under maximum likelihood, distance, and parsimony criteria. Melastomeae are closest to Microlicieae, a clade currently appearing endemic in the neotropics. Melastomeae-type seeds have been reported from the Early Miocene of Eurasia (~20 MYBP), while the oldest records for the family are Paleocene (~60 MYBP) pollen grains from Colombia and leaves from North America. A molecular phylogeny of Melastomataceae (Clausing and Renner, submitted) shows Melastomeae branching off relatively late and paleotropical Melastomeae forming a clade within neotropical Melastomeae. This suggests a relatively recent neotropical origin of Melastomeae, followed by dispersal to North America, Africa and Europe, Madagascar, SE Asia, and Australia. Molecular clock estimates, using rbcL and ndhF genetic distances calibrated with the fossils, imply a mid-Tertiary age for the separation between Central American and North American genera, and arrival and dispersal of Melastoma and Osbeckia in SE Asia from Africa/Madagascar during the Pliocene.

Key words: long distance dispersal, Melastoma, molecular clock, Osbeckia, Rhexia