Systematics of Tibouchina and allies (Melastomataceae: Melastomateae): A new taxonomic classification

Abstract

Tibouchina (Melastomataceae: Melastomateae) is an exclusively Neotropical genus that currently includes close to 310 species. These were first described or assigned to 16 other genera, a reflection of the complex taxonomic and phylogenetic history of the genus. Previous phylogenetic analyses have shown that the genus is polyphyletic. Here we present an expanded analysis that includes representatives of 28 genera of New World Melastomateae, as well as representatives of Old World Melastomateae and members of the Marcetieae and Microlicieae. Over 300 species were sequenced for nrITS and the plastid spacers accD‐psaI and psbK‐psbL. We recovered a large clade of Neotropical Melastomateae that contains Tibouchina along with at least 13 other Neotropical genera. Moreover, Tibouchina is not recovered as monophyletic because three mostly Central American and five mostly Andean genera are nested within it, albeit each these genera are recovered as monophyletic. Many of the previously recognized sections of Tibouchina are recovered as monophyletic or paraphyletic providing a basis for a new classification. Tibouchina is here re‐circumscribed into four genera that are each monophyletic and easily diagnosable. This results in a narrowly circumscribed Tibouchina and the re‐establishment of Pleroma and Chaetogastra, and the description of a new genus, Andesanthus. Pleroma now also includes Itatiaia, Microlepis and Svitramia. Brachyotum is maintained until its relationship to Chaetogastra can be further examined. This new taxonomic arrangement is more informative and convenient than merging eight other genera into Tibouchina. An identification key, descriptions of genera, and lists of taxa with their current generic assignment and necessary nomenclatural novelties are also presented here.

A Guide to Curating New World Melastomataceae Collections with a Linear Generic Sequence to World-Wide Melastomataceae

“…The linear sequence provided here is based on a compilation of recent published and unpublished phylogenetic analyses (Clausing et al 2000, Clausing and Renner 2001a, Clausing and Renner 2001b, Michelangeli et al 2004, Amorim et al 2009, Penneys et al 2010, Michelangeli et al 2011, Goldenberg et al 2012, Penneys 2013, Penneys and Judd 2013a, Goldenberg et al 2015, Kriebel et al 2015, Rocha et al 2016a, Rocha et al 2016b, Veranso-Libalah et al 2017, Dellinger et al 2018, Rocha et al 2018, Veranso-Libalah et al 2018, Bacci et al 2019, Bochorny et al 2019, Guimarães et al 2019, Veranso-Libalah et al 2019, Wurdack and Michelangeli 2019, Zhou et al 2019a, Zhou et al 2019b. The number of species per genus and comments on generic limits are based on the systematic and/or monographic studies cited below.…”

“…A new world tribe of three genera of small shrubs and herbs. Two of the genera (Arthrostemma and Pachyloma) had been placed in Melastomateae (Renner 1993), but molecular and seed morphology place it with Rhexia , Rocha et al 2016a, Guimarães et al 2019). Arthrostemma does not have a formal revision, but all four species occur in Mesoamerica, thus the treatment for the family of this area serves as a revision (Almeda 2009).…”

“…The circumscription the African genera has recently been addressed (Veranso-Libalah et al 2017, Veranso-Libalah et al 2019, Veranso-Libalah et al 2020. Within Neotropical Melastomateae the large genus Tibouchina has been recently segregated into four smaller genera, Andeasanthus, Chaetogastra, Pleroma, and Tibouchina (Guimarães et al 2019), with Pleroma also including Itatiaia, Microlepis, Svitramia, and Tibouchinopsis (Da Silva et al 2014, Romero and Alves Versiane 2014, Guimarães et al 2019. Monographs for neotropical genera are available for Andesanthus (as Tibouchina sect.…”

The Regulation of Floral Colour Change in Pleroma raddianum (DC.) Gardner

“…The scientific name of this species, classically known as Tibouchina pulchra (Cham.) Cogn, has recently changed [ 1 ]. Its use for urban ornamentation is increasing due to its colourful flowers.…”

The importance of rediscovering rare and endemic plants: Two species of Pleroma D.Don (Melastomataceae), an update of conservation status, and improved descriptions

“…Pleroma D.Don is a neotropical genus of Melastomataceae with 157 species, which are mainly distributed in eastern Brazil, occurring primarily in the Atlantic Forest and Cerrado biomes and rarely in the Caatinga (Guimarães et al 2019). Pleroma is now considered a distinct genus from Tibouchina Aubl.…”