North America, Eurasia.
Genera 19, species ca. 450 (4 genera, 23 species in the flora).
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.
|1||Petals almost completely connate, spongy; plants climbing, petiolules and reduced leaflets twining and tendril-like.||Adlumia|
|1||Petals coherent or connate only basally, not spongy; plants not climbing.||> 2|
|2||Both outer petals swollen or spurred basally.||Dicentra|
|2||Only 1 outer petal swollen or spurred basally.||> 3|
|3||Fruit an elongate, dehiscent capsule; seeds more than 1, with elaiosome.||Corydalis|
|3||Fruit a ± globose, indehiscent capsule; seeds 1, without elaiosome.||Fumaria|