A revised genus­level taxonomy for Trimezieae (Iridaceae) based on expanded molecular and morphological analyses

Abstract

AbstractTrimezieae is a Neotropical tribe of Iridaceae. It is widely distributed in Central and South America with species diversity centered on Brazil. Previous studies have consistently found that although the tribe itself is monophyletic, as currently recognized three of the four genera within it are not. Using an enlarged sampling of taxa, molecular markers and morphological characters, the present study further improves our understanding. Our molecular phylogenetic analyses confirm the broad­scale relationships observed in earlier studies. That is, four principal clades are well supported but links between them remain uncertain. A broad morphological survey identified diagnostic characters for several clades; these were primarily vegetative, including features of the underground stems, leaves and flowering stems. Based on these findings we present a new genericlevel classification that recognizes groups that were well supported in phylogenetic analyses and are clearly distinguished on morphological grounds. This framework requires new circumscriptions for three of the existing generic­level taxa, as well as the recognition of a new genus within the tribe.