The phylogenetic relationships within Styrax series Valvatae were estimated with DNA sequence data from the internal transcribed spacer region of nuclear ribosomal DNA to test hypotheses bearing on the historical biogeography of the Antilles. The results provide evidence for three dispersal events within Styrax to the Antilles, one from southern North America, the other two from South America. The data do not support a strict Greater Antillean vicariance scenario for Styrax. Vicariance between the Greater Antilles and southern North America without immediate prior dispersal would require a more basal position of Styrax ochraceus than that recovered, although low branch support values in the relevant portion of the tree do not preclude this possibility. Dispersal of Styrax from South America to the Greater Antilles could have proceeded across oceanic barriers, or more likely through GAARlandia. Styrax obtusifolius in Cuba and Hispaniola and the strictly South American Foveolaria clade have evolved small flowers and the gynodioecious condition independently. The predominance of microscopic pollinators in the Cuban fauna may have impelled the evolution of small flowers in Styrax obtusifolius. The data suggest that the Antilles have played little if any role in the intercontinental dispersal of Styrax.