Geographical distribution and diversity in a collection of the tropical legume Macroptilium gracile (Poeppiga ex Bentham) Urban

Abstract

A collection of 53 accessions of the American legume Macroptilium gracile was grown and classified using 23 attributes. Ten groups from this extremely diverse collection were defined on the basis of the presence of amphicarpy (the ability to set both aerial and subterranean seed) and a small set of morphological and phenological attributes. The resultant classification has provided a framework for the selection of representative accessions from the collection for evaluation studies. Comparisons of provenance data from this collection and those of herbarium material from major North American herbaria highlighted both the lack of germplasm from the Caribbean region and poor representation of herbarium material from south of the Amazon basin. The variation in the collection supported the combination of M. longepedunculatum and M. gracile, but the morphological and geographic diversity suggests that the current taxonomic treatment should be revised.