BEYRA M., ANGELA AND MATT LAVIN.* Filial del Instituto de Ecología y Sistemática, Ministerio de Ciencia Technología y Medio Ambiente, Camagüey, C. P. 70100, Cuba. and Department of Biology, Montana State University, Bozeman, MT 59717. - Phylogenetic systematics of Pictetia (Leguminosae) with a preliminary circumscription of aeschynomenoid legumes.

The genus Pictetia, with nine species confined to the Greater Antilles, includes the traditionally recognized genus Belairia. Pictetia is diagnosed by pods with a two-nerved placental margin, leaves with long shoots subtended by spinescent stipules, coriaceous leaflets with spinescent mucros, and short shoots covered by persistent distichous stipules. These morphological synapomorphies, as well as ones derived from the analysis of 5.8S and flanking ITS sequence data, support the hypothesis of monophyly for the genus. All species except P. spinifolia are confined to a single island system in the Greater Antilles. Historical biogeographic analysis supports a close area relationship of eastern Cuba, central Hispaniola, and Puerto Rico, which is consistent with Rosen’s Caribbean vicariance hypothesis. Pictetia occupies a pivotal position within the aeschynomenoid legumes. It has been classified in the plesiomorph-rich subtribe Ormocarpinieae, which is shown to be paraphyletic with respect to other aeschynomenoid genera. Among the genera of Ormocarpinieae, Pictetia is most closely related to the North American mainland genus Diphysa, the African-Asian genus Ormocarpum, and the Madagascan genus Ormocarpopsis. These four genera represent an early branching clade within the aeschynomenoid radiation. Analysis of non-molecular data suggests that Ormocarpum and Ormocarpopsis are sister to Pictetia, whereas analysis of ITS sequence data reveals a sister group relationship of Diphysa and Pictetia. Regardless, the close area relationship of Mexico and the Greater Antilles with Africa, Asia, and Madagascar is considered relictual from a Tertiary boreotropic distribution. Phylogenetic analysis reveals that the nine species of Pictetia are not conveniently grouped into infrageneric taxa. The four Belairia species have accumulated so many morphological synapomorphies, they are referred to as the Belairia Pictetias. The remaining species of the genus are referred to individually.