ABSTRACT
Acianthera Scheidew. comprises about 200 species with Neotropical distribution; in the most recent proposal of taxonomic synopsis for the genus, Chiron & van den Berg created 10 sections, among which Acianthera sect. Pleurobotryae, subject of this study. The section Pleurobotryae can be distinguished from other Acianthera sections by the long unguiculate lip with a mobile articulation, and the cylindrical to laterally flattened leaves, attached to a thread like cauloma. Their specimens are rather distributed in Southern and Southeastern Brazil and Northeastern Argentina. In this work a taxonomic study of the section Pleurobotryae is presented. Three new synonyms and a new combination are proposed for the group. Of the six species previously assigned to this section, only four are accepted here: Acianthera atropurpurea (Barb.Rodr.) Chiron & van den Berg, A. crepiniana (Cogn.) Chiron & van den Berg, A. hatschbachii (Schltr.) Chiron & van den Berg, and A. mantiquyrana (Barb.Rodr.) V.T. Rodrigues & F. Barros.
Atlantic forest; Epidendroideae; Pleurobotryum; Pleurothallis
