Herbs , annual or perennial, scapose or caulescent, from taproots, bulblets, tubers, or rhizomes; sap clear. Stems when present leafy, erect to prostrate or climbing, simple or branching. Leaves basal and/or cauline, alternate, mostly compound, sometimes simple, without stipules, petiolate; blade with 2-6 odd-pinnate orders of leaflets and/or lobes. Inflorescences terminal, axillary, extra-axillary, or leaf-opposed, unifloral or else multifloral and thyrsoid, paniculate, racemose, or corymbose; peduncles present; bracts present. Flowers bilaterally symmetric about 1 plane or each of 2 perpendicular planes; pedicel present; sepals caducous or persistent, 2, thin; petals 4, distinct or coherent basally to almost completely connate, in 2 whorls of 2; outer petals alike or dissimilar, 1 or both sometimes swollen or spurred basally; inner petals alike, apically connate, clawed, with somewhat hollow, membranous, wrinkled, abaxial median crests; stamens 6, in 2 bundles of 3 each, opposite outer petals; filaments of each bundle partially to completely connate, sometimes basally adnate to petals, with basal nectariferous tissue often in form of spur; anthers connivent, adhering to stigma, median anthers 2-locular, lateral anthers 1-locular; pistil 1, 2-carpellate; ovary 1-locular; placentae parietal; style threadlike, rigid; stigma 1, compressed, with 2 lobes or apical horns, and/or 2-8 papillar stigmatic surfaces. Fruits capsular, indehiscent or dehiscent and valvate. Seeds 1-many, small, elaiosome (oil-bearing appendage) often present.

The genera of Fumariaceae are distributed mostly in the Old World and primarily in temperate Eurasia. One acaulescent species of Dicentra occurs in Siberia, Kamchatka, and Japan; a caulescent species is found in western China and northern Burma; and nine climbing species are distributed throughout the Himalayan area and Burma. More than 400 taxa of Corydalis and 50 of Fumaria , distributed primarily throughout temperate, often montane, regions of Eurasia and Africa, have been described. Adlumia comprises only two species, which are quite similar morphologically, one from North America and the other from East Asia.

Most European and some American systematists treat Fumariaceae as a subfamily of Papaveraceae. However, although a few taxa are morphologically intermediate, the members of Fumariaceae generally are quite distinct from those of Papaveraceae in several respects, including floral symmetry, sap character, and stamen number and fusion.

PLANT: Annual or short-lived perennial herbs. LEAVES: exstipulate, cauline or basal, alternate, dissected, glabrous. INFLORESCENCE: racemes or panicles. FLOWERS: perfect, zygomorphic, hypogynous; sepals 2, deciduous; petals 4, the outer 2 larger with saccate or spurred bases, the inner 2 narrower and converging over the stigma and anthers, keeled or not on back; stamens 6, in 2 groups of 3, opposite outer petals; middle anther of each set 2-celled, the outer anthers 1-celled; filaments united; pistil 2-carpellate; style 1, persistent or deciduous; stigma bilobed. FRUIT: a 1-locular nutlet or capsule. SEEDS: 1-many, black, shiny, round to round-reniform. NOTES: 19 genera; ca. 400 spp, mostly N. Temp. A few species of Corydalis and Dicentra are ornamentals. Fumaria officinalis is an agricultural weed. REFERENCES: Holiay, Susan, and Abril Perez. 2001. Commelinaceae. J. Ariz. - Nev. Acad. Sci. Volume 33(1).