Previous analyses of species relationships and polyploid origins in the mimosoid legume genusLeucaena have used chloroplast DNA (<sub>cp</sub>DNA) restriction site data and morphology. Here the authors present an analysis of a new DNA sequence data set for the nuclear ribosomal DNA (<sub>nr</sub>DNA) 5.8S subunit and flanking ITS 1 and ITS 2 spacers, a simultaneous analysis of the morphology, ITS and <sub>cp</sub>DNA data sets for the diploid species, and a detailed comparison of the <sub>cp</sub>DNA and ITS gene trees, which include multiple accessions of all five tetraploid species. Significant new insights into species relationships and polyploid origins, including that of the economically important tropical forage tree L. leucocephala, are discussed.
American Journal of Botany (2002) 89 (7) 1057-1073
Divergent and reticulate species relationships in Leucaena (Fabaceae) inferred from multiple data sources: insights into polyploid origins and NR DNA polymorphism