Phylogenetic relationships in Senegalia (Leguminosae-Mimosoideae) emphasizing the South American lineages

Senegalia is a genus of the legume family (Leguminosae: Mimosoideae) that has a pantropical distribution with centers of diversity in Brazil, Mexico and southern Africa. The genus is characterized by plants having bipinnate leaves, presence of petiolar nectaries, prickles on the branches, and pollen grains arranged in polyads with 16 grains. Morphology is an important tool for identification of Senegalia species, but it is not sufficient to resolve all taxonomic issues and elucidate the evolutionary history of this genus. Prior molecular analyses of Mimosoideae have lacked breadth of sampling within Senegalia, leaving many relationships uncertain, particularly the relationship among Brazilian species and other members of the genus. The aim of this study was to identify Senegalia s. s. lineages that contain Brazilian species, and to investigate the relationship of these species with non-Brazilian Senegalia species. We present the first comprehensively sampled phylogeny of American and Af...