Fifty-eight new species from regions north and west of Brazil are described and illustrated in miscellaneous genera of the Pleurothallidinae. A new combination in Crocodeilanthe, C. bracteosa, is proposed, as well as the new generic name Lalexia to replace the invalid name Loddigesia. A new combination in Lalexia, L. quadrifida is also proposed. Pleurothallis ringens is transferred to Talpinaria and recognized as distinct from Pleurothallis hitchcockii (= Talpinaria hitchcockii). These two species are discussed and described, and the treatment of Talpinaria hitchcockii in Icones Pleurothallidinarum XVI is revised. Porroglossum miguelangelii, originally described for Ecuador, is placed in synonymy with Porroglossum tokachii, a species heretofore known only from Amazonian Peru. In alphabetical order, the new species proposed herein are: Acianthera cornejoi, A. fernandezii, A.tanyae; Acronia miniatura, A. niesseniae, A. rinkei, A. werneri, Alaticaulia amsleri, A. cracens, Ancipitia dubbeldamii, A.renieana, Crocodeilanthe franciscensis, C.juxta, C. mendietae, C. speciosa, C. werneri, Dracula gerhardii, Effusiella werneri, Kraenzlinella rinkei, Lepanthes anemica, L.barclaya, L. brevipedicellata, L. carrilloi, L. chocoënsis, L. ericae, L. eucerca, L. heteroloba, L.juan-felipei, L. lacera, L. macdougalii, L. maria-victoriae, L. medinae, L. pictoris, L. reburra; Luzama dejonghei; Masdevallia odnalorii, M. sentinella; Octomeria werneri; Porroglossum adrianae, P. apoloae, P. dejonghei, P. ecuagenerense, P. myosurotum; Regalia antonii; Restrepia peetersii; Rodrigoa ruthiana; Scaphosepalum rinkei; Stelis compressicauls, S. conduplicata, S. discrepans, S. franciscensis, S. malvina, S. modica, S. pilulosa, S. regia, S. rudolphiana, S. thelephora, and S. tyria.
Twenty-nine new species are described and illustrated in miscellaneous genera of the Pleurothallidinae. In alphabetical order, the new species proposed herein are Acianthera macilenta; Acronia hirtzii, A. rhinocera; Apoda-prorepentia hirtzii; Elongatia driessenii; Lepanthes dissidens, L. holoserica, L. licrophora, L. orlicii, L. praetermissa, L. vanbalenii; Masdevallia tonii; Porroglossum acrobat, P. sororcula; Scaphosepaluin translucens; Stelis agatha, S. agonzalezii, S. aspergilliformis, S. atroculata, S. celesticola, S. chaetostoma, S. chemophora, S. cracens, S. eudialema, S. habrostachya, S. leptoschesa, S. microsynema, S. sarae, and S. somnolenta.
Two new Brazilian species of the orchid genus Acianthera, Acianthera calopedilon and Acianthera cephalopodiglossa, are described and illustrated. The identities of Acianthera bidentula, Acianthera saundersiana, and Acianthera serpentula are discussed. Acianthera velteniana, recently described for Espírito Santo, is placed in the synonymy of Acianthera bidentula. An epitype is selected for Pleurothallis saundersiana and a lectotype for Pleurothallis serpentula. Updated synonymy lists are provided for the taxa treated in the article.