Annual to perennial glabrous taprooted herb, 30-80 cm tall; rootstock woody; stems erect, ribbed, hollow, branched above. Lvs obovate-cuneate, (2)-4-10-(15) × (1)-2-5-(6) cm, pinnatifid with 5-10-(15) pairs of entire, oblong to linear lobes, constricted above lobes; margins tuberculate, flat or undulate. Pedicels patent, 2-5 mm long. Sepals 5-6, narrow-ovate. Petals white, 5-6, all with 3-(5)-lobed limbs. Stamens 11-14; filaments persistent. Capsule oblong to ellipsoid, smooth, (6)-8-12 × 2-4 mm; carpels 4. Seeds brown to dark brown, tuberculate, dull, 1-1.5 mm long.