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.

Symplocos dasyphylla Brand é uma das espécies menos conhecidas de Symplocos que ocorre no Rio de Janeiro. Esta espécie tem sido erroneamente considerada um sinônimo de S. itatiaiae Wawra e a descrição original de S. dasyphylla não contem todos os caracteres necessários para reconhecer a espécie. É fonecida uma descrição revisada e aumentada, lectotipificação, ilustração, citação de materiais examinados, dados para avaliar seu estado de conservação, e uma chave para as espécies de Symplocos seção Hopea ocorrentes no Rio de Janeiro.

Symplocos dasyphylla Brand is one of the most poorly known species of Symplocos occurring in Rio de Janeiro. This species has been erroneously considered a synonym of S. itatiaiae Wawra, and the original description of S. dasyphylla does not contain the characters needed to diagnose the species. Here we provide a revised augmented description of S. dasyphylla, lectotypification, illustration, citations of material examined, data for assessing its conservation status, and a key to the species of Symplocos section Hopea occurring in Rio de Janeiro.