We present a taxonomic revision of Dactylaena and Haptocarpum as part of a series of generic revisions and delimitation of Neotropical Cleomaceae. Two new species are described, Dactylaena boliviensis and D. zmarztyae, one new combination is made, D. monandra, four lectotypes are designated in Dactylaena, and a key to all species is presented. This is the first comprehensive revision of the now seven recognized species of Dactylaena and provides needed clarification of species boundaries, distributions, and diversity. Haptocarpum is maintained as a monotypic genus.