Proc. Amer. Acad. Arts 10: 69. 1874.
Plants perennial, glaucous, from large, fleshy roots. Stems 1-several, 10-15 dm or more. Leaves ca. 5, compound, to 10 dm; blade with 2-4 orders of leaflets and lobes; ultimate lobes of proximal cauline leaves narrowly to broadly elliptic, 1-5 cm, apiculate. Inflorescences paniculate, 50 or more flowers on primary axis; bracts inconspicuous, linear or narrowly elliptic, rarely wider, proximal bracts ca. 10 mm, distal greatly reduced. Flowers ascending or spreading; pedicel 3-5 mm; sepals persistent, round and irregularly dentate to ovate, lunate, or attenuate-lanceolate with broad, sometimes lobed base, 2-3 mm; petals light pink to white, inner ones tipped reddish purple; spurred petal often incurved, 16-25 mm, spur tapered or not, 9-16 mm, apex obtuse, crest absent, inconspicuous, or extending into beak beyond petal apices, marginal wing narrow to broad, conspicuous; unspurred outer petal 10-15 mm; inner petals 7-12 mm, claw 3-5 mm; nectariferous spur 1/2-3/4 length of petal spur; style 3-4 mm; stigma roughly rectangular, with 8 papillae. Capsules reflexed, ellipsoid, 10-15 × ca. 3-5 mm. Seeds ca. 2.5 mm diam., with numerous minute protuberances.
Calif., Colo., Idaho, N.Mex., Oreg., Utah
Subspecies 5 (5 in the flora).
Significant livestock losses have been caused by ingestion of Corydalis caseana, which is palatable to both cattle and sheep, despite the toxicity.
|1||Outer petals with marginal wing narrow or absent, apex of unspurred outer petal acute; California.||Corydalis caseana subsp. caseana|
|1||Outer petals with marginal wing moderately to highly developed, apex of unspurred outer petal not acute; other than California.||> 2|
|2||Outer petals with marginal wing scarcely revolute, apex rounded, sometimes minutely apiculate or notched.||> 3|
|2||Outer petals with marginal wing distinctly revolute, apex distinctly notched.||> 4|
|3||Outer petals minutely apiculate; stems mostly 10–15 dm; Colorado and New Mexico.||Corydalis caseana subsp. brandegei|
|3||Outer petals not minutely apiculate, occasionally minutely notched; stems mostly 4–10 dm; Utah.||Corydalis caseana subsp. brachycarpa|
|4||Inflorescences profusely branching; outer petals with marginal wing moderately developed, minutely eroded; n Idaho.||Corydalis caseana subsp. hastata|
|4||Inflorescences not profusely branching; outer petals with marginal wing highly developed, not minutely eroded; ne Oregon and s Idaho.||Corydalis caseana subsp. cusickii|