Plants 30-90 cm, glabrous or sparsely pubescent. Leaves: petioles ca. 0.5 cm; blades 2.5-6.5 cm, ultimate lobes to 1 mm wide, margins usually spinulose-ciliate, apices acute to obtuse. Peduncles 10-30 cm. Calyculi of spreading to reflexed, linear-oblong to narrowly lanceolate bractlets 6-9 mm, apices acute. Involucres (3-)5-10(-15) mm diam. Phyllaries erect, oblong, 5-8 mm, apices acute. Ray corollas white to rose-pink or violet, laminae cuneate-obovate, 5-9 mm, apices dentate. Disc corollas 4-5 mm. Cypselae 9-16 mm, setulose; pappi of 2-4 erect awns 2-3 mm. 2n = 24. Flowering summer-fall. Open or forested slopes and canyons, sometimes in disturbed and cultivated areas; 100-3000 m; Ariz., Colo., Md., Mass., Mo., N.Mex., R.I., Tex.; Mexico. Within the flora area, Cosmos parviflorus is native only in the southwestern United States.