Independent Origin of Radial Floral Symmetry in the Gloxinieae (Gesnerioideae: Gesneriaceae) is Supported by the Rediscovery of Phinaea pulchella in Cuba

Phinaea, in the currently accepted circumscription, is a genus in the flowering plant family Gesneriaceae with three widely disjunct species. These species are known from small populations in Mexico, northern South America, and the West Indies (Cuba and Haiti), respectively. Phinaea pulchella is one of the few members of the tribe Gloxinieae that occurs naturally in the West Indies and it is the only member of the tribe endemic to that region. It was rediscovered in Cuba in 2008, more than fifty years after it was last documented. Results from molecular data generated from the nrDNA ITS and cpDNA trnL-F regions strongly support that P. pulchella does not group with other Phinaea species and instead shares a recent common ancestor with Diastema vexans in a clade that is sister to Pearcea and Kohleria. The phylogenetic placement of P. pulchella suggests that radial floral symmetry and buzz-pollination is autapmorphic in this taxon. Our results strongly support convergence of radial symmetry and associated characters with buzz-pollination in the following taxa in the tribe Gloxinieae: Niphaea, Phinaea s. s., Phinaea pulchella, and Amalophyllon. New generic circumscriptions based on the results presented here are not suggested until more complete taxon sampling includes additional species currently recognized in Amalophyllon.