Annuals, (10-)30-70(-150+) cm. Leaves: proximal blades usually 1(-3)-pinnate, terminal lobes lance-ovate to oblanceolate, 10-60 × 5-25 mm; cauline blades usually 1-2(-3)-pinnate, rarely simple, simple blades or terminal lobes lance-linear to linear or filiform, 10-45 × 0.5-2(-5+) mm. Peduncles 1-5(-15+) cm. Calyculi of deltate-lanceolate bractlets 1-3+ mm. Phyllaries ± lance-oblong to lance-ovate, 4-7(-9) mm. Ray laminae usually yellow with red-brown blotch, sometimes red-brown in proximal ¹/3-⁹/10 and distally yellow, rarely yellow throughout, 12-18+ mm. Disc corollas 2.5-3+ mm. Cypselae 1.5-3(-4+) mm, wings 0 or 0.1-0.7+ mm wide; pappi 0, or of 1-2 cusps or subulate scales 0.1-1+ mm. 2n = 24 (+ 0-2 Bs). Flowering year round, mostly Jun-Aug. Moist, sandy or clay soils, sometimes alkaline flats, prairies, ditches, disturbed places; (0-)20-1500(-2000) m; Alta., B.C., Man., Ont., Que., Sask.; Ala., Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Vt., Va., Wash., W.Va., Wis., Wyo.; Mexico (Coahuila, Nuevo León, Tamaulipas).

Plant: Annual 3-12 dm, glabrous; stem generally 1, erect, much-branched above Leaves: opposite; petiole 1-2 cm; blade 3-12 cm, lower 1-2 X divided into linear to narrowly lanceolate, entire lobes, upper simple, linear INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads radiate, many in open, leafy-bracted cymes; peduncles 4-10 cm; involucre bell-shaped; outer phyllaries 7-8, 1-3 mm, triangular; inner phyllaries 4.5-8 mm, ovate, obtuse or acute; chaff scales 4-5 mm, linear, red-orange, free from disk achenes Flowers: Ray flowers generally 8; ligules 6-20 mm, yellow (or base red-brown); Disk flowers many; corollas ± 3 mm, 4-lobed, reddish; style tips truncate to long-tapered Fruit: 1.5-2.8 mm, linear-oblong to widely elliptic, black, smooth or minutely rough; wing 0 to wide; pappus 0 Misc: Disturbed places; < 1000 m.