Phylogenetic relationships, infrageneric classification and species limits in the Neotropical genus Faramea (Coussareeae: Rubiaceae)

Abstract

Abstract Faramea is characterized by white or blue, tetramerous corollas and blue-black, fleshy fruits with a single, large pyrene. Both infrageneric relationships and species boundaries are poorly understood in the genus. This study represents the first broad-scale phylogenetic study of Faramea, with 80 of the c. 170 species sampled, 24 by two or more specimens. We aimed to include specimens representing the entire geographical, morphological and ecological ranges of the genus. Morphological characters historically utilized to delimit infrageneric sections in Faramea (e.g. bract and pyrene forms) were also evaluated. Only one of the currently accepted infrageneric sections was recovered as monophyletic (within a complex of species from other sections) and none of the morphological features traditionally utilized to determine infrageneric relationships in the genus was found to be uniquely diagnostic of a larger clade. Some Faramea lineages appear to be geographically isolated, with several clades containing solely specimens collected in the Atlantic Forest biomes. Of the 24 species represented by at least two specimens, 11 were supported as monophyletic, ten as non-monophyletic and three were not resolved as either monophyletic nor non-monophyletic. The results of the present study constitute a good basis for future studies of taxonomy, biogeography and ecology of Faramea.