This widesread weed was originally centered in the southern Great Plains, but it is adventive at scattered sites across southeastern states (Cr, W). The only records from Ky. are colls. from BALL and HICK at SIU, duplicated at NCU (Mohlenbrock et al. 1966). It differs from caroliniense in its narrower leaves (ca. 1-3 cm versus 2-8 cm, and l/w ca. 3-6 versus 2), which are entire to sinuate (versus irregularly lobed or cleft) and silvery-canescent (versus loosely hairy), with stellate hairs ca. 0.5 mm wide and at least 12 rayed (versus 1-2 mm and ca. 5-rayed); stems are sparsely spiny to spineless (versus consistently spiny); 2n = 24 and 72 (versus just 24). Plants have complex chemistry, interacting with various ecological and physiological processes. It is toxic to mammalian herbivores, especially cattle, due to the glycoalkaloids solanine and solasonine (Buck et al. 1960, Boyd et al. 1984).