The history of the taxonomy of Pleurothallis R.Br. subsection Macrophyllae-Fasciculatae and recent descriptions in that group are summarized. The phylogenetic position of the group based on preliminary molecular data and the appropriateness of the proposed genera Acronia C.Presl. and Zosterophyllanthos Szlach. & Marg. for this group are discussed. Three new species from northern South America are described: Pleurothallis rubrifolia from southeastern Ecuador and northeastern Peru; Pleurothallis nangaritzae from southeastern Ecuador; and Pleurothallis castanea. Labellar micromorphology examined by scanning electron microscopy for P. rubrifolia and P. nangaritzae is discussed in relation to taxonomy and possible pollinator interactions.

Pleurothallis minutilabia, a species unique in subsection Macrophyllae-Fasciculatae because of the minute, highly reduced lip, is described and compared to the most similar species in the subsection. It is also compared morphologically to Pleurothallis kaynagata from section Abortivae, to which P. minutilabia is not related, but which also possesses a highly reduced lip. The morphology of the flower of P. minutilabia is discussed briefly in relation to possible pollination mechanisms. The distribution, restricted to Zamora Chinchipe, southern Ecuador, and the conservation status are addressed. Key words / Palabras clave: cloud forest, Ecuador, labellar morphology, Pleurothallis, pollination

A new species, Pleurothallis ecomingae, from near Chical, Carchi Province, Ecuador, is described and illustrated. This species is unique in that it has characteristics typical of both subgenera Scopula and Ancipitia. The plant has narrowly lanceolate leaves with a near-apical fascicle of single-flowered peduncles, previously only seen in Scopula. And, it has flowers with a minute, pubescent, tri-lobed lip in which the basal lobes are modified into ‘horns’, and an apical orifice in the central lobe, a feature previously only seen in Ancipitia. This intermediate morphology supports the previous suggestion that, at least based on morphology, the two subgenera should be combined.

A new species of Pleurothallis in subsection Macrophyllae-Fasciculatae from Ecuador is described, illustrated and its relationship with other species is discussed. Pleurothallis chicalensis is compared with P. dewildei, from which is distinguished by the ovate leaves, the yellow flowers with broadly obovate synsepal and the transversely cordate lip with apiculate apex.resuMen. Una especie nueva de Pleurothallis de la subsección Macrophyllae-Fasciculatae de Ecuador es descrita, ilustrada y su afinidad con otras especies es discutida. Pleurothallis chicalensis se compara con P. dewildei, de la cual difiere por las hojas ovadas, las flores amarillas con el sinsépalo ampliamente obovado y el labelo transversalmente cordado con el ápice apiculado.

Lepanthes vere-aurum, a new species of the orchid subtribe Pleurothallidinae, discovered in Zamora Chinchipe province, southeast Ecuador, is described here. We compare L. vere-aurum to L. brenneri, the only similar species, from which it differs in having larger leaves and longer inflorescences. Also, L. vere-aurum has an obovate, concave, long-acuminate dorsal sepal and a concave appendix with a pubescent crest underneath and with a long, pubescent apex,versus a flat, triangular-ovate, acuminate dorsal sepal and a smaller appendix with a ciliate apex in L. brenneri. Some information about its phenology and ecology is additionally provided. Key Words: Cordillera del Cóndor, endangered orchid, Epidendroideae, Lepanthes brenneri, new orchid species