Phylogenetic relationships of Scaphyglottis and related genera (Laeliinae: Orchidaceae) based on nrDNA ITS sequence data. Brittonia 56: 58–66. 2004.—Sequences of the nuclear ribosomal internal transcribed spacer regions 1 & 2 (nrDNA ITS) including the intervening 5.8S region were analyzed cladistically for 43 individuals of 35 species of Scaphyglottis s.l. plus two outgroup taxa. Low levels of sequence divergence do not allow estimation of relationships among most clades, but the analyses indicate that four segregate genera (Hexisea Lindl., Reichenbachanthus Barb. Rodr., Hexadesmia Brogn., and Platyglottis coriacea L.O. Williams) are embedded within a broad paraphyletic Scaphyglottis. This broadly defined Scaphyglottis sensu Dressler is characterized within Laeliinae by the usual presence of superposed growth habit and the presence of a column foot. In order to accommodate species formerly placed in Platyglottis and Reichenbachanthus, three new combinations are made in Scaphyglottis: Scaphyglottis brasiliensis (Schltr.) Dressler, S. coriacea (L. O. Williams) Dressler, and S. emarginata (Garay) Dressler.