In some treatments before 1950 (e.g. B), this widespread southeastern diploid (2n = 20) was misnamed C. virginianum (L.) Michx., a closely related species that occurs just on the southeastern Coastal Plain (2n = 28). In Ky. carolinianum appears to be a somewhat conservative biennial in remnants of thin woodland and grassland, especially on sandy soils in Appalachian regions with a long history of disturbance.