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

Paulo José Fernandes Guimaraes,Diego Nunes Da Silva,Caio Baez,Patrícia Rosa,Gustavo Martinelli

doi:10.36253/jopt-8902

Paulo José Fernandes Guimaraes, Diego Nunes Da Silva + Show 3 more

Open Access

https://doi.org/10.36253/jopt-8902

Copy DOI

Abstract

The remaining portion of Atlantic Forest in the state of Rio de Janeiro constitutes a strategic challenge in the conservation of the biome, by concentrating high richness and endemism of species that are distributed in distinct vegetative fragments covering the mountainous regions. In the state, the genus Pleroma presents a high diversity, currently 45 species, of which 14 are endemic and several of these have knowledge gaps. This paper aims to document rediscoveries in the Três Picos State Park of two species of Pleroma that had not been collected for 69 and 100 years respectively. These discoveries resulted from the actions of the National Center for Plant Conservation, a division of the Rio de Janeiro Botanical Garden. Updated descriptions, geographic information and distribution maps, and cited collections for these two species of Pleroma are presented here together with an assessment of their current conservation status. Based on IUCN criteria, we recommend a classification of Critically Endangered (CR) and Endangered (EN) for Pleroma virgatum and P. elegans, respectively.

Highlights

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 distinguished from the other genera of Melastomateae Neotropical by presenting stamens with well-developed pedoconnectives and purple or pink anthers and, if pedoconnectives have trichomes, they are glandular, and the calyx lobes are deciduous in fruits (Guimarães et al 2019)
Two other species remain without any new record in nature for over 46 years: Pleroma cristatum (Brade) P.J.F.Guim. & Michelang. was last found in 1938 in Santa Maria Madalena (Brade 1938) and P. pallidum (Cogn.) P.J.F.Guim. & Michelang. recorded in the city of Rio de Janeiro at Pedra da Gávea in 1973 (Cogniaux 1885; Rosa et al 2018)

Summary

Introduction

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). In Rio de Janeiro state, Brazil, Pleroma is represented so far by 45 species, and of these, 14 species are endemic to the state (P.J.F. Guimarães and D.N. Silva in prep.). Two species that are rare and endemic in the state of Rio de Janeiro, Pleroma thereminianum (DC.) Triana and P. cleistoflorum (Ule) P.J.F.Guim., Oliveira da Silva & Michelang., were studied regarding geographic distribution patterns in order to recommend conservation strategies (Pinheiro 2013). Of the other species endemic to the state, two are known only by the type collection: Pleroma schwackei (Cogn.) P.J.F.Guim. Two other species remain without any new record in nature for over 46 years: Pleroma cristatum (Brade) P.J.F.Guim. & Michelang. was last found in 1938 in Santa Maria Madalena (Brade 1938) and P. pallidum (Cogn.) P.J.F.Guim. & Michelang. recorded in the city of Rio de Janeiro at Pedra da Gávea in 1973 (Cogniaux 1885; Rosa et al 2018)

Objectives

Methods

Results

Conclusion