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.

The genus Lepanthes Swartz (1799a: 85) with more than 1200 species (Bogarín et al. 2018) is the largest genus in Pleurothallidinae, comparable only with Stelis Swartz (1799b: 239). It is distributed throughout the Neotropics from central Mexico and the Antilles south to Peru and Bolivia, with only few species occurring in Brazil (Luer & Thoerle 2012). The diversity of Lepanthes species in Peru is probably underestimated. About 58–64 species have been formally recorded (Tropicos 2016, Govaerts et al. 2016, Damian & Larsen 2017), which is relatively fewer compared to neighbouring countries where the genus is relatively well known, such as Colombia and Ecuador, each with more than 300 species (Thoerle & Hirtz, 2015). At the moment, several new species and new records of the genus for the country are awaiting publication, and as more extensive exploration continues, the number of Lepanthes attributed to Peru is expected to increase.

aBstract. In this paper we summarize the taxonomic history of Pleurothallis crocodiliceps Rchb.f. and demonstrate that the species described by Reichenbach did not possess the stereotypical minute, pubescent, tri-lobed lip, with basal lobes modified into "horns". The first two species described with such a lip were P. arietina and P. nelsonii. Rather than a single widely distributed, variable species, with a morphologically constant lip, P. crocodiliceps, we recognize the P. arietina-P. nelsonii species complex. Herein we describe four new species in this complex and discuss the morphological characters useful in distinguishing among the members of the complex. We also discuss the nature of the lip possessed by members of this complex and propose that it may mimic a female insect luring a male fly into pollinating the flower by pseudocopulation.

aBstract. Pleurothallis trimeroglossa has long been considered a synonym of P. talpinaria. In this study we reviewed types, descriptions, drawings, paintings and living material for both names and concluded that P. talpinaria and P. trimeroglossa should be recognized as distinct species. An anatomical structure important in the distinction between the two is the large dome-shaped callus at the base of the lip in P. trimeroglossa. The approximate distributions and elevational ranges of the two species are discussed. During the study we recognized a novel species, described here as Pleurothallis jostii. Labellar morphology of all three species was examined. We speculate on the pollination mechanism of this group of species based on the observations of labellar micro-morphology.