XVI International Botanical Congess

The West Indian moss flora, with about 714 species and varieties, is widely represented in North America (Mexico), Central and South America. There are northward and southward trends in the distribution of taxa that suggest, along with the overall similarity of the moss flora of each area, that mosses dispersed to Cuba, Jamaica, Hispaniola and the Lesser Antilles in Pliocene and Pleistocene times. A vicariant event is not favored as the explanation for most patterns of distribution because much of the islands surface was underwater when rafting was completed. A dendrogram resulting from an UPGMA cluster analysis of the similarity matrix shows that Haiti, Dominican Republic and Jamaica exhibit floristic differences among them and with their neighbors that seem to be consistent with the a non-vicariant origin of the moss floras..