Revision of the genus Leucaena in Mexico.
A taxonomic revision is presented of this genus of shrubs and trees native to America with its centre of diversity lying across Mexico. On the basis of existing literature and a study of morphology and geographical distribution, new infraspecific taxa are described (with Latin diagnoses) belonging to the species L. confertiflora, L. cuspidata, L. esculenta and L. lanceolata, together with the new species L. involucrata. Two lectotypes are designated, an interspecific hybrid L. × brachycarpa is recognized, and nomenclature and synonyms are established, including 3 new combinations. In all, 22 taxa are included (14 species, 18 subspecies), for which a key is provided, together with data on distribution, habitat, phenology, common name and uses.