A monograph of neotropical Potalia Aublet (Gentianaceae: Potalieae)

The first revision of the neotropical genus Potalia (Gentianaceae: Potalieae, formerly Loganiaceae) is presented. This genus was formerly considered monotypic, with Potalia amara being the only recognized species. New morphological and anatomical studies show that Potalia resinifera should be resurrected and that nine newly discovered species should be recognized; one endemic to Central America (P. turbinata), two endemic to Chocó, Colombia (P. chocoensis and P. crassa), two endemic to white-sand areas along Rio Negro and its tributaries (P. elegans and P. maguireorum; Brazil, Colombia, and Venezuela), and the last two endemic to white-sand areas in the western Amazon basin (P. coronata and P. yanamonoensis; Peru, Brazil and Colombia). Potalia amara sensu stricto is restricted to the Guianas and northeast Brazil, whereas P. resinifera is widespread in lowland Amazonia and the Andean foothills. Morphological differences between the species are primarily in fruit and inflorescence morphology, but there are also differences in plant size, leaf shape, and corolla color. Potalia resinifera shows the greatest infraspecific variation. Phylogenetic relationships between Potalia and its close relatives Anthocleista from Africa and Fagraea from tropical Asia-Australia-Pacifics are discussed. The widespread pharmacological uses of Potalia species by indigenous peoples of the Neotropics are reviewed and vernacular names are listed.