Annual; roots all fibrous. Stems moderately stout, erect, pubescent above, 10-30-(50) cm tall. Basal lvs subcircular, shallowly 3-5-lobed, 2-4 × 2-4 cm, glabrous; petioles glabrous, 1.5-3 cm long. Cauline lvs 2-ternate; leaflets linear, 2-3-fid, pubescent; uppermost lvs becoming subsessile. Fls 3-7-(15) per stem, 15-20 mm diam. Pedicels erect, pubescent, terete, c. 50 mm long at fruiting. Sepals 5, with sparse long hairs, subacute, 6-7 mm long, spreading, pale yellow. Petals 5, pale yellow, obovate, c. 10 × 6 mm; nectary single, c. 0.5 mm from petal base, covered by a short broad truncate scale. Receptacle hairy. Achenes 5-8, strongly flattened, distinctly bordered, broadly obovate; body 5-7 × 4-5 mm; face with strong long curved spines especially near the margin; beak straight, 2-3 mm long.