Three Mexican endemic species of shrubby habit and apparent thelypodioid affinities (lodanthus acuminatus, I. mexicanus, and I. petiolatus) are separated from the eastern North American herb lodanthus pinnatifidus as the genus Chaunanthus O. E. Schulz. The new combinations Chaunanthus acuminatus and C. mexicanus are proposed. The distinguishing features and geographic distribution of the genus Chaunanthus are discussed, and a key to species and synopsis of its three included species are presented.