Phylogenetic relationships in the genus Stylosanthes (Leguminosae) based upon chloroplast DNA variation

A detailed analysis of chloroplast DNA restriction fragment length variation was undertaken to reconstruct the maternal phylogeny of 18 taxa from both sections of the papilionoid tropical forage legume genus Stylosanthes. Data were analysed by means of the computer program PAUP, using an heuristic search with Wagner parsimony. The resulting cladogram divided Stylosanthes into four separate clades, which comprised: (i) the S. guianensis complex and related species (i.e. S. gracilis, S. grandifolia and S. mon tevidensis); (ii) S. hispida, tetraploid S. hamata s. 1., S. sympodialis, S. humilis, S. leiocarpa, S. angustifolia and certain accesions of S. scabra; (iii) S. calcicola, S. viscosa, diploid S. hamata s. str., and S. fruticosa, plus accessions of S. scabra, S. capitata and one accession of S. grandifolia; and (iv) S. macrocephala and other accessions of S. capitata not included within clade 3. Results are generally congruent with previously established interspecific relationships and, moreover, enabled identification of putative maternal progenitors for four tetraploid taxa: S. humilis was identified as a Likely maternal parent of both S. sympodialis and S. hamata s. 1., S. viscosa as a maternal parent of S. scabra, and S. macrocephala as a maternal parent of S. capitata.