A taxonomic study of the genus <I>Tibouchina</I> Aubl. (Melastomataceae) in Rio Grande do Sul – Brazil

Abstract

This research consists in a taxonomic study of the genus Tibouchina Aubl. (Melastomataceae) in the State of Rio Grande do Sul (Brazil). Were analysed exsicata from several herbaria in Brazil and Argentine, as well as "in vivo" material during many incursions through the state's different physiographic regions. Was carried a bibliographical search to the genus, with the main works obtained. Are presented keys to the determination of Melastomataceae's genera and to Tibouchina's species of Rio Grande do sul. Were found, until this moment, to the state, 17 species of the genus Tibouchina: T. asperior (Cham.) Cogn., T. cerastifolia (Naud.) Cogn., T. cisplatensis Cogn., T. clinopodifoia (DC.) Cogn., T. debilis (Cham.) Cogn., T. dubia (Cham.) Cogn., T. gracilis (Bonpl.) Cogn., T. herbacea (DC.) Cogn., T. hospita (DC.) Cogn., T. longipilosa Cogn., T. ramboi Brade, T. rupestris Cogn., T. sellowiana (Cham.) Cogn., T. trichopoda (DC.) Baill., T. urbanii Cogn., T. urvilleana (DC.) Cogn. e T. versicolor (Lindl.) Cogn., T. longipilosa e T. urbanii are cited here for the first time to the state. To each species were made a description, comments, illustrations, and a map showing the collections distribution.