S. lingua and S. vomeracea are very similar, the major difference is that S. vomeracea has two keels that are parallel down the midlobe of the lip to the apex. In S. lingua there is only one. Images of this plant appear to show a keel on either side of the midvein. Photos of S. vomeracea in orchidroots.com are a close match to this plant. The long, hairy lip is the distinquishing feature of S. vomeracea, the Long-Lipped tongue orchid. There is some variability in the colors of the flowers.