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.