Annual to perennial, glab. to pubescent, erect to prostrate herbs; simple to much-branched, 3-60 cm. tall, with solitary to ∞ capitula corymbosely arranged. Lvs 1-6 cm. long, fleshy to membr., entire to toothed or variously lobed or pinnatifid; lobes broad-oblong to linear, obtuse to acute, toothed or not; petiolate to sessile, with or without amplexicaul bases. Capitula 5-20 mm. diam.; phyll. 10-15, linear, acute, us. distinctly 2-ribbed, reflexed in age, us. with a few small linear ones at base, forming a subamplexicaul involucre; ray-florets 10-15 or absent; ligules yellow, short to long, spreading to recurved, sts revolute; disk-florets ∞, about = involucre. Achenes linear, grooved, pubescent to glab., up to c. 3 mm. long; pappus-hairs us. cop., slender, finely to distinctly barbellate.

2n = 40

n = 20

n = 20

n = 20

2n = 40

2n = 40

n = 20

Prostrate to ascending, or erect, annual or short-lived perennial herb. Lvs glabrous or sparsely hairy, cuneately narrowed at base and often appearing petiolate, narrow-ovate, elliptic, oblong, or lanceolate, not lobed and entire, irregularly pinnately toothed, or lobed with many lvs usually pinnatifid with narrow to broad, entire or few-toothed, usually distant segments, 15-65-(110) × (3)-5-15-(60) mm; primary segments, lobes, or teeth (0)-3-6-(7) on each side. Uppermost lvs smaller, less divided, often amplexicaul. Supplementary bracts 6-16, 1-3 mm long. Involucral bracts (8)-10-13-(15), 4-6.5 mm long, usually glabrous, sometimes with a few scattered hairs. Ray florets 7-13 (extremely rarely 0); ligules yellow, (1)-2-7-(9) mm long. Disc yellow, 3-6 mm diam. Achenes usually densely hairy only between ribs, very rarely glabrous or ± evenly hairy, slightly narrowed to apex, 2.2-3 mm long.