Perennial herb, 50-80cm high. leaves alternate, long-petiolate; lower stem leaves are 2-ternate-pinnate, branch ends are simple; leaflets are narrowly ovate, lanceolate or elliptic, with cartilaginous denticles at the margins. Flowers terminal and axillary; sepals 4, purplish red; petals 6-9, white, pink or purplish red; stamens numerous; carpels 4-5, glabrous or densely covered with white hairs, carinae ovate, apex externally curved into a hook. Flowering in June, fruiting in August to September.