A PHYLOGENETIC ANALYSIS OF LEUCAENA (LEGUMINOSAE, MIMOSOIDEAE)

Chloroplast DNA restriction fragment length polymorphisms have been us ed to reconstruct the maternal phylogeny of all the known taxa in the small neotropical legume genus Leucaena. Three major plastome clades w ere recognized, but these did not conform with relationships between t he taxa proposed on other characters from morphology, cytology or hybr idization. The maternal parentage of tetraploids within the genus has been proposed. Evidence for introgression was found between ''diploid' ' L. diversifolia and ''tetraploid'' L. diversifolia. The implications of these results for the origin of the cultivated taxa are discussed.