Description from Flora of China
Herbs, annual. Leaves bipinnatipartite, petiolate; lobes narrow; lobules linear, sometimes ovate-oblong, glabrous or pubescent. Flowers solitary, terminal, axillary, or terminal to leaf, pedicellate. Sepals 2, caducous, pubescent. Petals 4, purple, mauve, or red, overlapping in bud. Stamens many. Ovary terete, 2-4-carpellate, 1-loculed; styles short; stigmas capitate, 2-4-divided. Capsule narrowly terete, siliquose, (2-)4-valved, divided from apex to base. Seeds many, reniform, not carunculate, seed coat alveolate.
About seven species: Mediterranean region to C and SW Asia; two species in China.
(Authors: Zhang Mingli (张明理); Christopher Grey-Wilson)