Taxonomic revision of the neotropical genus Homalolepis Turcz. (Simaroubaceae)

Homalolepis Turcz. is a neotropical, monophyletic genus, recently reestablished as a segregate from Simaba Aubl., based on molecular and morphological grounds. As here defined, Homalolepis comprises 28 species, mainly distributed in tropical South America, with one species extending to Central America. Most species occur within the Cerrado and Atlantic forest domains in Brazil and only a few species occur in the Caatinga and Amazonian domains or in other countries. Most of the species are narrow endemics, and two (H. suaveolens and H. maiana) are presumably extinct. The present revision treatment is primarily based on the examination of about 1300 specimens from 58 herbaria. Natural populations of 20 species were also studied. Extensive field work improved the representativeness of collections of several species which were poorly known until now, and it was critical for achieving accurate species circumscriptions, especially for some species complexes present in the genus. Twenty-three species were transferred from Simaba to Homalolepis, seven names lectotypified, an epitype designated, seven new species described, and one reestablished. The infrageneric classification is reevaluated, with an updated morphological circumscription of two traditional sections. This revision provides the taxonomic data on nomenclatural types, including synonymies, morphological descriptions, etymology of species names, common names and uses, illustrations and photos, and brief discussions on phenology, taxonomy and nomenclature. Distribution maps are provided for each species, along with biogeographical and ecological comments.