Description from Flora of China
Herbs, summer annual, glaucous, glabrous, with slender taproot. Stems angular, leafy and branched throughout. Leaves alternate, 2 or 3(or 4) × pinnate, or lower leaves 2 or 3 × ternatisect; lower leaves long petiolate; upper leaves shortly petiolate or sessile. Inflorescences leaf-opposed [i.e., displaced-terminal], racemose, subspicate, soon elongating; bracts linear-oblong, scarious. Flowers zygomorphic, on short pedicels. Sepals petaloid, dentate. Upper outer petal with short saccate spur; inner petals fused at apex; nectary short, obtuse. Stamens 2 (= filaments of each triplet completely fused). Stigma transversely oblong, with indistinct papillae. Fruit a ± globular nut, with 2 small depressions at apex. All species self-compatible, and many predominantly selfing.
When grown in shade or under severe water stress, plants of Fumaria tend to be longer and more lax and the flowers smaller, paler, and often cleistogamous.
Fifty species: Canary Islands to C Asia, most diverse in N Africa and SW Europe, one species in E Africa, a few species widely naturalized as weeds; two species in China.
(Authors: Zhang Mingli (张明理); Magnus Lidén)