AbstractLiterature and herbarium studies of Thuidiaceae in Latin America show that at least 477 specific names have been applied to members of this family in Latin America. Many of these have been reduced to synonymity or transferred from one genus to another or to another family by earlier workers. About 30nom. nud. (unpublished) were found applied to specimens in various herbaria. These are not considered in this paper. Statistical analyses (phenetic similarity and taxonomic distance) and more detailed morphological studies of herbarium specimens, especially types, have further reduced the total to the ninety-six species here recognized, by the present author, as being valid. Keys to genera and species are included with species description, habitat, and geographic distribution for each of the ninety-six species in ten genera.