This monotypic genus occurs in east-central states, usually in riparian or other submesic woods on seasonally damp fertile soils. It is the only native mustard typical of such habitats in Ky. Although generally described as perennial, Iodanthus appears to be short-lived in cultivation, not persisting or spreading except perhaps where there is fresh disturbed soil for seedling establishment. As noted by W. it "somewhat resembles Hesperis matronalis in overall appearance" but differs in the following characters: petals 10-13 mm long (versus 20-25 mm long), pale purplish to whitish (versus deep purple to white), siliques 2-4 cm long (versus 5-10 cm long), hairs of lower stem sparse, simple (versus dense, simple and branched).