Annual (rarely perennating) often scandent herbs, glabrous or subglabrous, glaucous, with almost all cauline leaves, irregularly 2-4 pinnatisect with many usually very narrow segments. Racemes short, generally leaf-opposed, bracteolate; bracts often short, linear, rarely as long or slightly longer than pedicel. Flowers small, zygomorphic, white, pink or purplish, very much like Corydalis but spur very short. Sepals 2 or obsolete. Petals 4, only the upper spurred; spur much shorter than the lamina; inner 2 narrower than the outer ones; lower petal keeled. Ovary 1-celled, usually suborbicular with 1 (-2) ovules on each placenta; style short, often filiform with entire to somewhat lobed stigma. Fruit a I-seeded, ± globose nut, rugulose or smooth when dry, with 2 apical pits; seed usually large, suborbicular, brownish.
About 50 species, chiefly of the temperate and cooler regions of the old world and often as weeds; only 2 species are recorded for our area.
A difficult genus and most of the species are variable, affected by light and shade conditions. Sometimes plants grown in shade have small cleistogamous flowers and a typical leaf segment. Flower colour fades under preserved condition and must be noted when fresh. The fruit is sometimes joined by the expanded top of the pedicel by a narrow fleshy neck, distinct only in fresh conditions, which also must be noted during the time of collection.