Annual. Roots tap and fibrous. Stem erect, simple or branched, finely grooved or ribbed, glabrous, 50-120 cm tall. Lvs soft, dull to ± shiny, mid to dark green to glaucous above, pale to glaucous beneath, glabrous, ± oblanceolate to obovate; margins dentate with spinulose teeth. Rosette and lower stem lvs (4)-10-20 × (1.5)-4-10 cm, pinnatifid almost to midrib; lobes reflexed or recurved, ovate to narrowly triangular; petiole narrowly winged. Upper lvs pinnatifid, usually with broadly triangular terminal lobe, 1-3 pairs of narrowly triangular lateral lobes, a broadly expanded winged petiole, and an amplexicaul-auriculate base with pointed lobes, sometimes lf not lobed, ovate-amplexicaul, rarely pinnatisect with linear lobes. Infl. cymose to umbellate; capitula few to many. Involucre 10-15 mm long, turbinate to cylindric; bracts imbricate, reflexed at fruiting, usually glabrous or rarely with a few pale glandular or eglandular setae. Receptacle glabrous. Florets 11/2× length of involucre; corolla tube c. = ligule; ligules spreading, yellow. Achenes narrowly obovoid to clavate, brown, weakly flattened, 2.5-3 × 0.8-1 mm, 3-ribbed on each face, not winged; ribs and spaces between finely transversely wrinkled. Pappus fine, white, c. = involucre.