1b. ssp. occidentalis (Engelm. ex A. Gray) G.B. Ownbey

C. curvisiliqua Engelm. ssp. occidentalis (Engelm.) W.A. Weber

C. montana Engelm.

Inflorescences with 5–12(–20) flowers, usually extending past the foliage. Corollas with the upper outer petal 14–18 mm long, the spur 5–9 mm long, the concave apical portion usually with a low irregular crest. Fruits 15–18(–20) mm long, usually curved, ascending at maturity. Seeds sharply angled along the rim, with a minute, marginal ridge. March–June.

Scattered widely, mostly south of the Missouri River (Nevada to Arizona east to South Dakota, Illinois, and Texas; Mexico). Glades, upland prairies, openings of dry upland forests, and banks of streams; also railroads and roadsides.

Corydalis aurea ssp. occidentalis is most often found growing on acidic substrates. Although it is less widely distributed than Steyermark (1963) thought it to be, it is much more abundant in the state than the single site in the Kansas City region that was mapped by Stern (1997a).