A phylogenetic analysis of Leucaena (Leguminosae: Mimosoideae).
Chloroplast DNA RFLPs, utilizing 14 restriction enzymes, were used to reconstruct the maternal phylogeny of all the known taxa (17 species from 24 taxa) in the small neotropical genus Leucaena. Three major plastome clades were recognized, but these did not conform with relationships between the taxa proposed on other characters from morphology, cytology or hybridization. The maternal parentage of tetraploids within the genus was proposed. Evidence for introgression was found between the putative diploid and tetraploid forms of L. diversifolia. The implications of these results for the origin of the cultivated taxa are discussed.