Annuals, (10-)20-80+ cm. Leaves: petioles 5-25 mm; blades rounded-deltate overall, 25-90+ × 15-35+ mm, (1-)2(-3)-pinnatisect, ultimate lobes lance-rhombic or ovate to lanceolate, 15-30(-50+) × 5-15(-30+) mm, bases truncate to cuneate, ultimate margins entire or ± serrate to incised, usually ciliolate, apices obtuse to acuminate, faces glabrous. Heads usually borne singly, sometimes in open, ± corymbiform arrays. Peduncles (10-)30-50(-150+) mm. Calyculi of 8-13 usually spreading, narrowly lanceolate, oblanceolate, or subulate to linear bractlets 2-5 mm, margins entire, usually ciliate, abaxial faces usually glabrous. Involucres ± campanulate, 2.5-5+ × 1.5-3(-4) mm. Phyllaries 8-13+, lanceolate, (3-)4-6+ mm. Ray florets 0 or 1(-5+); laminae whitish, 1-3(-7) mm. Disc florets 13-25+; corollas yellowish, 1-2 mm. Cypselae: outer red-brown, obcompressed, cuneate, 6-7 mm, margins not ciliate, apices truncate, faces 2-grooved, antrorsely tuberculate-hirtellous; inner dark brown to blackish, ± equally 4-angled, linear-fusiform, 10-14 mm, margins not ciliate, apices ± attenuate, faces glabrous; pappi of 2(-3), erect, retrorsely barbed awns (1-)2-4 mm. Flowering Sep. Along streams, other wettish sites; 900-2000 m; Ariz., Colo., N.Mex., Okla., Tex.; Mexico.