Abstract
Phylogenetic relationships for a large number of Brazilian species of Pleurothallis sensi lato (Acianthera, Anathallis, Pabstiella and Specklinia) were inferred in an analysis of ITS nrDNA using both parsimony and Bayesian methods. Our results show that: 1) most Brazilian Pleurothallis species recently transferred into Stelis in fact belong to the genus Pabstiella; 2) groups of species previously generally considered to be part of the genus Specklinia belong to Pabstiella; 3) some infrageneric groups—mostly compatible with Luer's sectional organization of his Pleurothallis subgenus Acianthera—are clearly supported within Acianthera; and 4) two species could represent a new genus.