Croton section Crotonopsis is very distinctive within the genus. It is one of the few groups of the genus that are endemic to the United States. Although the precise phylogenetic relationships of section Crotonopsis have not been established in molecular studies, it is clearly nested within Croton. We hypothesize that it may form a clade with some of the other sections found in North America that have lepidote trichomes and multifid styles. The two species that have been recognized in the section are very similar morphologically; we therefore propose that these two taxa should be included as varieties of a single species and formalize the varietal names, which are Croton michauxii var. michauxii and the new combination C. michauxii var. elliptica. A key to distinguish the two varieties is presented.