A taxonomic synopsis of the Mexican species of Acianthera (Orchidaceae: Pleurothallidinae) including a new species

Acianthera pollardiana is herein described as a new species based on specimens collected in Oaxaca, Mexico. Information concerning the distribution, habitat, phenology and conservation status for this taxon is provided. In addition, traits that distinguish this species from similar taxa are mentioned, and a line drawing, photograph, and a map of known localities are also shown. A taxonomic synopsis of Mexican Acianthera in which twenty species are accepted is also provided. Acianthera herrerae, whose presence has only previously been recorded in Guatemala, is here reported for first time for the Mexican flora. Acianthera javieri, A. markii, and A. martinezii are placed under the synonymy of A. angustisepala, A. tikalensis, and A. hondurensis, respectively. Moreover, an artificial key for Acianthera species is included in this synopsis and maps of known localities in Mexico are presented.