Data from: DNA sequence variation among conspecific accessions of the legume Coursetia caribaea reveals geographically localized clades here ranked as species

Coursetia caribaea is geographically and morphologically the most variable
species in the genus Coursetia and in the tribe Robinieae (Leguminosae,
Papilionoideae). Because of potentially undetected species, we assessed
the phylogenetic relationships among the eight taxonomic varieties of C.
caribaea. Sampling included nuclear ribosomal internal transcribed spacer
sequences from 489 Robinieae accessions representing all varieties of C.
caribaea and 38 of the 40 species of Coursetia, in addition to chloroplast
trnD-trnT sequences from 186 accessions. Separate and combined
phylogenetic analyses resolved a clade of conspecific accessions of the
Bolivian C. caribaea var. astragalina as sister to the central Andean
Coursetia grandiflora clade. Also distantly related to Coursetia caribaea
var. caribaea accessions were those of the coastal Oaxacan C. caribaea
var. pacifica, which formed the sister clade to accessions of the central
Andean C. caribaea var. ochroleuca. The estimated mean ages of the stem
clades for these three lineages, 11, 7.7, and 7.7 Ma, respectively,
contrasted to the estimated mean ages of the corresponding crown clades of
0, 0, and 1.5 Ma. The contrasting stem and crown ages suggest that these
taxa, appropriately ranked as species, Coursetia astragalina, Coursetia
diversifolia, and Coursetia ochroleuca, each have persisted over
evolutionary time frames as distinct geographically localized populations
in seasonally dry tropical forests and woodlands.