Tibouchina Octopetala

''Tibouchina'' "Tibouchina." Webster's Third New International Dictionary of the English Language, Unabridged. Merriam Webster, 1961. is a neotropical flowering plant genus in the family Melastomataceae. Species of this genus are subshrubs, shrubs or small trees and typically have purple flowers. They are native to Mexico, the Caribbean, and South America where they are found as far south as northern Argentina. Members of this genus are known as glory bushes, glory trees or princess flowers. The name ''Tibouchina'' is adapted from a Guianan indigenous name for a member of this genus. A systematic study in 2013 showed that as then circumscribed the genus was paraphyletic, and in 2019 the genus was split into a more narrowly circumscribed ''Tibouchina'', two re-established genera ''Pleroma'' and ''Chaetogastra'', and a new genus, ''Andesanthus''.

Description

''Tibouchina'' species are subshrubs, shrubs or small trees. Their leaves are opposite, usually with petioles, and often covered with scales. The inflorescence is a panicle or some modification of a panicle with reduced branching. The individual flowers have five free petals, purple or lilac in color; the color does not change as the flowers age. There are ten stamens, either all the same or dimorphic, with five larger and five smaller ones. The connective tissue below the anthers of the stamens is prolonged and modified at the base of the stamens into ventrally bilobed appendages. When mature, the seeds are contained in a dry, semiwoody capsule and are cochleate (spiralled).

Taxonomy

The genus ''Tibouchina'' was established by Aublet in 1775 in his Flora of French Guiana with the description of a single species, '' T. aspera'', which is thus the type species. In 1885, in his treatment for ''Flora brasiliensis'', Alfred Cogniaux used a broad concept of the genus, transferring into it many of the species at that time placed in ''Chaetogastra'', ''Diplostegium'', ''Lasiandra'', ''Pleroma'' and ''Purpurella'', among others. This broad concept was generally adopted subsequently, and around 470 taxa were at one time or another assigned to ''Tibouchina''.

Phylogeny

A phylogenetic analysis in 2013 based on molecular data (2 plastid and 1 nuclear regions) determined that the traditional circumscription of ''Tibouchina'' was paraphyletic. Four major clades were resolved within the genus which were supported by morphological, molecular and geographic evidence. Based on the traditional code of nomenclature, the clade that the type species falls in retains the name of the genus; therefore, the clade containing ''Tibouchina aspera'' remains ''Tibouchina''.

A further molecular phylogenetic study in 2019 used the same molecular markers but included more species. It reached the same conclusion: the original broadly circumscribed ''Tibouchina'' consisted of four monophyletic clades. The authors proposed a split into four genera: a more narrowly circumscribed ''Tibouchina'', two re-established genera ''Pleroma'' and ''Chaetogastra'', and a new genus, ''Andesanthus''. The relationship between ''Chaetogastra'' and the genus ''Brachyotum'' differed between a maximum likelihood analysis and a Bayesian inference analysis: the former found ''Brachyotum'' embedded within ''Chaetogastra'', the latter found the two to be sisters. The part of their maximum likelihood cladogram which includes former ''Tibouchina'' species is as follows, using their genus names and with shading added to show the original broadly circumscribed ''Tibouchina'' s.l.:

As re-circumscribed, ''Tibouchina'' is monophyletic and contains species belonging to the traditional sections ''T.'' section ''Tibouchina'' and ''T.'' section ''Barbigerae''. Diagnostic characteristics include the presence of scale-like trichomes on the hypanthium and leaves and a long pedoconnective on lilac anthers, and the absence of glandular trichomes. Species are found in savanna habitats.

Species

, Plants of the World Online accepts the following species within ''Tibouchina'':

*'' Tibouchina aegopogon'' (Naudin) Cogn.
*'' Tibouchina albescens'' Cogn. ex P.J.F.Guim., A.L.F.Oliveira & R.Romero
*'' Tibouchina alpestris'' Cogn.
*'' Tibouchina araguaiensis'' P.J.F.Guim.
*'' Tibouchina aspera'' Aubl.
*'' Tibouchina barbigera'' (Naudin) Baill.
*'' Tibouchina bicolor'' (Naudin) Cogn.
*'' Tibouchina bipenicillata'' (Naudin) Cogn.
*'' Tibouchina brevisepala'' Cogn.
*'' Tibouchina bruniana'' P.J.F.Guim.
*'' Tibouchina caatingae'' J.G.Freitas
*'' Tibouchina calycina'' Cogn.
*'' Tibouchina catharinae'' Pittier
*'' Tibouchina cujabensis'' Cogn.
*'' Tibouchina dissitiflora'' Wurdack
*'' Tibouchina duidae'' Gleason
*'' Tibouchina edmundoi'' Brade
*'' Tibouchina exasperata'' (Naudin) Cogn.
*'' Tibouchina fraterna'' N.E.Br.
*'' Tibouchina huberi'' Wurdack
*'' Tibouchina itatiaiae'' Cogn.
*'' Tibouchina johnwurdackiana'' Todzia
*'' Tibouchina karstenii'' Cogn.
*'' Tibouchina lithophila'' Wurdack
*'' Tibouchina lepidota'' P.J.F.Guim. & Michelang.
*'' Tibouchina llanorum'' Wurdack
*'' Tibouchina mathaei'' Cogn.
*'' Tibouchina melastomoides'' (Naudin) Cogn.
*'' Tibouchina nigricans'' Cogn. ex P.J.F.Guim., A.L.F.Oliveira & R.Romero
*'' Tibouchina octopetala'' Cogn.
*''Tibouchina papyrus'' (Pohl) Toledo
*'' Tibouchina pogonanthera'' (Naudin) Cogn.
*'' Tibouchina rosanae'' P.J.F.Guim. & Woodgyer
*'' Tibouchina sickii'' Brade
*'' Tibouchina sipapoana'' Gleason
*'' Tibouchina spruceana'' Cogn.
*'' Tibouchina steyermarkii'' Wurdack
*'' Tibouchina striphnocalyx'' (DC.) Pittier
*'' Tibouchina verticillaris'' Cogn.
*''Tibouchina xochiatencana'' de Santiago

Selected former species

Species placed in ''Tibouchina'' in its former broad sense include:

*''Tibouchina anderssonii'' Wurdack, synonym of ''Chaetogastra anderssonii''
*''Tibouchina asperior'' (Cham.) Cogn., synonym of '' Pleroma asperius''
*''Tibouchina campii'' Wurdack, synonym of '' Chaetogastra campii''
*''Tibouchina ciliaris'' (Vent.) Cogn., synonym of '' Chaetogastra ciliaris''
*''Tibouchina clinopodifolia'' (DC.) Cogn., synonym of '' Chaetogastra clinopodifolia''
*''Tibouchina elegans'' Cogn., synonym of '' Pleroma elegans''
*''Tibouchina francavillana'' Cogn., synonym of ''Pleroma francavillanum''
*''Tibouchina gleasoniana'' Wurdack, synonym of ''Andesanthus gleasonianus''
*''Tibouchina granulosa'', synonym of '' Pleroma granulosum''
*''Tibouchina gracilis'' (Bonpl.) Cogn., synonym of '' Chaetogastra gracilis''
*''Tibouchina grossa'', synonym of '' Chaetogastra grossa''
*''Tibouchina heteromalla'', synonym of ''Pleroma heteromallum'' - silver-leaved princess flower
*''Tibouchina lepidota'' (Bonpl.) Baill., synonym of ''Andesanthus lepidotus''
*''Tibouchina mollis'' (Bonpl.) Bonpl., synonym of ''Chaetogastra mollis''
*''Tibouchina mutabilis'' (Vell.) Cogn., synonym of ''Pleroma mutabile''
*''Tibouchina oroensis'' Gleason, synonym of '' Chaetogastra oroensis''
*''Tibouchina pereirae'' Brade & Markgr., synonym of '' Pleroma pereirae''
*''Tibouchina pulchra'' (Cham.) Cogn., synonym of '' Pleroma raddianum''
*''Tibouchina rufipilis'' (Schltdl.) Cogn., synonym of '' Chaetogastra rufipilis''
*''Tibouchina semidecandra'', synonym of '' Pleroma semidecandrum''
*''Tibouchina trichopoda'' (DC.) Baill., synonym of '' Pleroma trichopodum''
*''Tibouchina urvilleana'', synonym of '' Pleroma urvilleanum'' - princess flower, glory bush
*''Tibouchina versicolor'' (Lindl.) Cogn., synonym of '' Chaetogastra versicolor''

Distribution and invasive potential

All the species of ''Tibouchina'' are native to the Americas as far north as Mexico south to northern Argentina, with many found in Brazil, and others in Belize, Bolivia, Brazil, Colombia, Costa Rica, French Guiana, Guyana, Honduras, Nicaragua, Panama, Peru, Suriname, and Venezuela. Members of ''Tibouchina'' tend to be found in lowland savannas and on the lower slopes of the Andes. All ''Tibouchina'' species as well as those formerly placed in the genus are considered noxious weeds in Hawaii,Hawaii Administrative Rules, Title 4 Department of Agriculture, Subtitle 6 Division of Plant Industry, Chapter 68, Noxious Weed Rules (, cited 5 February 2007) because of their high potential for being invasive species.''Tibouchina urvilleana'': Pacific Island Ecosystems at Risk project IERdata (http://www.hear.org/pier/species/tibouchina_herbacea.htm, accessed 5 February 2007)Plants of Hawaii reports: ''Tibouchina longifolia'' (, accessed 5 February 2007)Plants of Hawaii reports: ''Tibouchina urvilleana'' (, accessed 5 February 2007) Many species, such as '' T. araguaiensis'', '' T. papyrus'', '' T. mathaei'' and '' T. nigricans'', have narrow distributions, being known from only a handful of locations, while a few other species, including '' T. aspera'', '' T. barbigera'' and '' T. bipenicillata'', have broader distributions.

References

External links

*
GRIN-Global Web v 1.9.7.1: Species of ''Tibouchina''

Flora Brasiliensis: ''Tibouchina''
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Flora of Central America
Flora of the Caribbean
Flora of Southern America
Flora of Brazil
Melastomataceae genera