This annual diploid (2n = 24) of the central and southern Great Plains appears to be only planted and adventive in Ky. The coll. from LARU (KY) has unusually large leaves with broader segments, suggesting hybridization with another species. A somewhat similar southeastern species, C. linifolia Nutt., has also been suggested in Ky., from reports under various synonyms, but its presence is dubious (M).