Annual; roots all fibrous. Stems moderately stout, erect, glabrous or very sparsely hairy, 10-30-(50) cm tall. Basal lvs subcircular, 3-5-lobed to c. 3/4 way, 3-5 × 3-5 cm; lobes obovate, cuneate, dentate, sparsely hairy on veins and margins; petioles glabrous, 5-15 cm long. Cauline lvs similar to basal but lobes becoming lanceolate, entire; uppermost lvs sometimes not lobed, lanceolate, entire. Fls 1-3-(10) per stem, 10-20 mm diam. Pedicels erecto-patent, sparsely hairy, terete, 15-60 mm at fruiting. Sepals 5 with sparse long hairs, acute, 5-6 mm long with apex deflexed at flowering. Petals 5, yellow, obovate, 7-9 × 3-4 mm; nectary single, 1-2 mm from petal base, covered by an obtuse to truncate scale. Receptacle hairy. Achenes 15-25, strongly flattened, distinctly bordered, broadly obovate; body 3-5-(7) × 2.5-3.5 mm; face with strong, long, curved spines especially near the margin; beak curved at tip, c. 2 mm long.