Threadsnakes of the tribe Epictini are endemic to the New World, occurring from the United States to Argentina, mostly in the Neotropical region. Currently, the taxonomic status of most species is unclear and there has been no previous attempt of a comprehensive taxonomic revision of Neotropical taxa. Taxonomy of the group is a difficult task due to the paucity of geographic samples, general homogeneous morphology and brevity of species descriptions. Therefore, the only way to address the taxonomic status of existing names is through detailed characterization of the types and the search for additional material of the poorly known species. In this study, we evaluated the taxonomic status of the Colombian threadsnakes and report on geographical variation of meristic, morphometric, colour pattern, and hemipenis characters. On the basis of available samples we recognize the following species in Colombia: Epictia goudotii, E. magnamaculata, E. signata, Rena nicefori, Tricheilostoma brevissimum, T. dugandi, T. joshuai and T. macrolepis. We discuss the systematic position of Rena nicefori and propose its allocation in the genus Tricheilostoma based on a unique combination of morphological characters. Furthermore, we provide a key to the representatives of the tribe Epictini in Colombia.

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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.

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.

New species of Masdevallia, Pleurothallis, Stelis, Trisetella and Zootrophion are described and illustrated, including three new forms of Masdevallia and one new form of Pleurothallis. New synonymy is provided for Acianthera dodsonii, Stelis pachyglossa, S. retusa, S. transversalis and Zootrophion serpentinum.