Phylogeny of Calliandra (Leguminosae: Mimosoideae) based on nuclear and plastid molecular markers

We reconstructed phylogenetic relationships in Leguminosae subfam. Mimosoideae tribe Ingeae using 135 sequences from the nuclear (ITS) and 119 from the plastid (trnL-F) genome, representing 23 of the 36 currently recognized genera in the tribe with newly generated sequences of Blanchetiodendron, Guinetia, Macrosamanea, Thailentadopsis and Viguieranthus and an extensive sampling of Calliandra. Only two of the five Neotropical generic alliances of Barneby & Grimes (1996) were supported as monophyletic. Calliandra is resolved as monophyletic with the inclusion of Guinetia. The five previously proposed sections within Calliandra were not supported by our study. Nevertheless, based on these results, a new infrageneric classification is proposed for Calliandra, and the African species of the genus are assigned to a new genus, Afrocalliandra. Three new sections are proposed for Calliandra: (1) sect. Tsugoideae based on C. ser. Tsugoideae, with four species from northwestern South America; (2) sect. Septentrionales, with six species distributed in dry areas from the United States to Mexico and (3) sect. Monticola, which consists of species restricted to the Espinhaco range of Brazil; these latter species form a clade with low levels of sequence variation, a potential indicator of the recent diversification of this group.