Tibouchina sect. Pleroma (D. Don) Cogn. (Melastomataceae) no estado de São Paulo

Abstract

The present work deals with the taxonomic study of the genus Tibouchina sect. Pleroma (D. Don) Cogn., aiming at an up to date revision ofthe genus. The study was based on the analysis of an number of exsicates (ca. 3200), including type specimens as well as the most important historicals collections, from Brazilian and foreign herbaria and also from collecting trips. The reproduction system of tow species of the genus was analyzed and the also a study of the tricomes and seeds of species was carried out using the scanning electronic microscope. The sect. Pleroma is characterized by lack of fruit persistent lacinias and the inflorescence axes well developed. Among the eleven sections composing the genus Tibouchina, the sect. Pleroma is the one which species have the closet affinities with the species of sect. lnvolucrales. They both are exclusively Brazilian in distribution and their fruits lack the persistent lacinias. The present review recognized 41 species in the sect. Pleroma for which the traditional taxonomic treatment was presented: identification key, descriptions, pertinent comments, illustrations, typification, list of examined materiaIs and distribution maps.