In this paper we present a revision of Charianthus, which represents the first genus in the Miconieae (Melastomataceae) to be the subject of a combined molecular and morphological cladistic analysis. Charianthus is a morphologically well-characterized clade of six species of hummingbird pollinated shrubs and small trees found in the tropical montane rain forests and elfin forests of the Lesser Antilles. Analysis of the internal transcribed spacer (ITS) region, combined with morphological data, resulted in a strongly supported Charianthus clade. Charianthus fadyenii was placed in the Tetrazygia clade where its position as sister to T. bicolor is strongly supported. Inclusion of C. fadyenii in Charianthus renders both Charianthus and Tetrazygia non-monophyletic, therefore, this species has been transferred to Tetrazygia. Charianthus purpureus, as defined by earlier taxonomists, is a polyphyletic species because of the inclusion of morphologically distinctive populations on the islands of Dominica and Grenada; thus, two new species, C. dominicensis and C. grenadensis, have been described, based on the results presented herein. The revised circumscription of Charianthus renders it the only vascular plant genus endemic to the Lesser Antilles.