Plants 10-60+ cm. Stems erect. Leaf blades rhombic-ovate to obovate, (20-)40-120(-150+) mm, faces finely pilosulous, gland-dotted. Fruits ± compressed, ± cuneate to obovate, 4-6+ mm, not notably ribbed, terminal spines 2, divergent, 3-4 mm, often 1 ± uncinate, prickles seldom notably uncinate, ± scattered. 2n = 22. Flowering year round, mostly Aug-Oct. Disturbed, often sandy sites; 0-100+ m; introduced; Ont.; Ala., Fla., Ga., N.J., Oreg., S.C., Va.; South America; also introduced in Mexico, West Indies, Central America, Europe, Asia, Africa, Pacific Islands (Hawaii).