Biennial to perennial glabrous taprooted herb, 30-80 cm tall; rootstock woody; stems and branches erect to ascending, ribbed, hollow, branched. Lvs obovate-cuneate, 2-10 × 1-7 cm; margins tuberculate, flat or undulate. Basal lvs not lobed or pinnatifid with 1-2 pairs of lobes; upper lvs pinnatifid, with 1-(3) pairs of lobes, constricted above lobes; lobes narrow-obovate, becoming linear, rarely again pinnatifid. Pedicels erecto-patent, (3)-5-8 mm long. Sepals usually 6, linear. Petals yellow, usually 6; limbs of posterior pair 3-fid, of lateral pair 2-3-fid, of anterior pair 1-(3)-fid. Stamens 12-20; filaments falling before fr. ripens. Capsule oblong to ellipsoid, usually tuberculate, rarely smooth, (6)-10-18 × (2)-5-8 mm long; carpels 3. Seeds black, smooth, shiny, 1.5-2 mm long.