Phylogenetic relationships and floral evolution in the papilionoid legume clade Amorpheae

Abstract

Amorpheae (Fabaceae: Papilionoideae) was first considered a natural group by Rupert Barneby in his illustrated monographDaleae Imagines. Amorpheae currently comprise eight genera, ca. 250 spp., and extensive floral diversity, including loss of corolla and addition of a stemonozone. The Amorpheae and many of Barneby’s subtribal groups are supported as monophyletic by previous phylogenetic analysis of nuclear ribosomal and chloroplast sequence data. However, some relationships remain unclear. A nuclear marker derived from a genomic study inMedicago CNGC 4, was sequenced in selected Amorpheae This is one of the first applications of this marker. for phylogenetic study. The new data confirm some relationships inferred usingtrnK and ITS, but also provide evidence for new arrangements. Combined data were used to explore several aspects of Barneby’s taxonomic framework. The phylogeny, in concert, with data on floral morphology, implies that simplification of the complex papilionoid flower has occurred several times in the history of the Amorpheae.