Phylogenetic patterns of diversification in the Beslerieae (Gesneriaceae)

Tribe Beslerieae constitute one of eight tribes currently recognized in Gesneriaceae subfamily Gesnerioideae and is currently considered to include seven genera: Anetanthus, Besleria, Cremosperma, Gasteranthus, Reldia, Resia, and Tylopsacas. Here we explore phylogenetic relationships among the major genera of Beslerieae, Besleria, Cremosperma, Gasteranthus, and Reldia, using nrDNA ITS sequences to explore generic monophyly, previous classification and phylogenetic hypotheses, and patterns of fruit-type evolution, stomatal cluster evolution, and biogeography. ITS data supports the monophyly of Besleria, Cremosperma, Gasteranthus, and Reldia, the intermediate position of fleshy capsules in the transformation of dry capsules to irregularly splitting or indehiscent berries, a single loss of stomatal clusters in the Beslerieae, and complex biogeographic patterns in the tribe but likely a single origin of Caribbean Besleria originating from northeastern South America.