A morphological phylogenetic analysis of Styrax (120 species) has suggested that no two of the four Antillean species of this genus form sister-group relationships: one groups in a clade of southern North American endemics, and the rest are each distributed among different clades of otherwise South American species. In particular, S. obtusifolius (Cuba and Hispaņola) has been considered the basal member in a clade of small-flowered, gynodioecious species otherwise endemic to South America. Here these relationships are tested with DNA sequence data from the ITS region. In contrast to the morphological analysis, phylogenetic analysis of the ITS data set recovers a strongly supported sister-group relationship between S. obtusifolius and the Puerto Rican endemic S. portoricensis, and this clade is nested within a group of fully bisexual South American species. The other two gynodioecious species sampled form a monophyletic group that is well removed from S. obtusifolius. Incongruence length difference tests suggest that overall conflict between the ITS and morphological data sets of neotropical evergreen Styrax is mainly attributable to the conflict between the data profiles in S. obtusifolius. All morphological characters supporting a relationship between S. obtusifolius and the other gynodioecious species are associated with gynodioecy and floral reduction, suggesting that the similarity in breeding system and floral characters among distantly related Cuban and South American species of Styrax represents a remarkable case of convergent evolution. This scenario is consistent with the prevalence of small-flowered species in the Cuban flora that have apparently coevolved with endemic and highly specialized microscopic insect pollinators, and with the trend toward dicliny on islands. Although Styrax is apparently boreotropical in origin, Antillean Styrax species have originated through dispersal from South America, as inferred from DIVA analysis. Styrax ochraceus, endemic to Hispaņola, still requires assessment in this context.

Key words: biogeography, Caribbean, DIVA, gynodioecy, ITS region, Styrax