Erect, glabrous or almost glabrous annual, 10-80 cm tall. Stems angled, branched above to form infl. Lvs petiolate, usually simple and not lobed, sometimes deeply 1-pinnatisect with 3-5 segments, 3-10-(20) cm long; lamina or segments narrowly ovate-elliptic to lanceolate, coarsely and often unevenly serrate, acuminate. Upper cauline lvs becoming smaller, shortly petiolate or apetiolate, not lobed and less distinctly serrate. Capitula 4-10 mm diam. Outer involucral bracts 3-4, foliaceous, glabrous, linear, 6-12 mm long; inner bracts many, membranous, ovate-elliptic to ovate-triangular, 5-8 mm long, with dark lined centre and pale margins. Receptacular scales similar to inner bracts but narrower. Florets all ☿, tubular, yellow-orange. Achenes flattened, ovate-cuneate to obtriangular, with 1 slender to prominent rib on each face, dark brown, ciliate and otherwise glabrous to sparsely hairy, 5-8 mm long; awns 2-4, often unequal, 0.5-2.7 mm long.