A new saxicolous species of Acisanthera (Melastomataceae: Marcetieae) from Chapada dos Guimarães National Park, Mato Grosso, Brazil

ABSTRACT

Acisanthera saxatilis is described, illustrated, and compared with putative relatives. The first specimen of this new species was collected 119 years ago by Oskar Andersson Gustaf Malme during his "second expedition Regnelliana". Acisanthera saxatilis is a little collected species apparently endemic to rocky sandstone formations in Chapada dos Guimarães, Mato Grosso state, Brazil. It differs from similar species by its perennial habit, lignotubers, isomorphic to slightly subisomorphic androecium, stamens positioned in a circle around the style during anthesis, antesepalous stamens with short connectives, small inconspicuous staminal appendages, and purple anthers. Photos of living specimens, a distribution map, scanning electron photographs of seeds and leaves, a preliminary conservation status assessment, as well as comments on vascular plant endemism at the Chapada dos Guimarães are provided.

Keywords:
Acisanthera; Brazil; Cerrado; Chapada dos Guimarães; Mato Grosso; neotropical region; endemism; endangered species.