Plants 30-200 cm, glabrous or sparsely pilose to hispid. Leaves: petioles 1-7 cm; blades 5-12(-25) cm, ultimate lobes 2-5 mm wide, margins sparsely spinulose-ciliate, apices apiculate. Peduncles 10-20 cm. Calyculi of spreading-ascending, linear-subulate bractlets 5-7(-10) mm, apices acute; Involucres 6-10 mm diam. Phyllaries erect, oblong-lanceolate, 9-13(-18) mm, apices acute to rounded-obtuse. Ray corollas intensely yellow to red-orange, laminae obovate, 18-30 mm, apices ± truncate, denticulate. Disc corollas 6-7 mm. Cypselae 15-30 mm, usually hispidulous, rarely glabrous; pappi 0, or of 2-3 widely divergent awns 1-7 mm. 2n = 24, 48. Flowering summer-fall. Disturbed sites; 0-1000 m; introduced; Ala., Ark., Calif., Conn., Del., Fla., Ga., Ill., La., Md., Mich., Mo., N.Y., N.C., Okla., Pa., S.C., Tenn., Tex., Va.; Mexico; also introduced in West Indies, Central America, South America, Asia, Africa, Pacific Islands.
Much like no. 1 [Cosmos bipinnatus Cav.]; ultimate lf-segments broadly linear to lanceolate, mostly (1.5-)2 mm wide or more; rays intensely orange-yellow or orange-red, 2-3 cm; achenes 15-30 mm; 2n=24. Native of trop. Amer., cult. and casually escaped toward the s. part of our range, and n. to Pa. Aug.-Oct.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
