Plants winter annual or biennial, glaucous, from ± branched caudices. Stems 10-50, prostrate-ascending, 2-3.5 dm. Leaves compound; blade with 3 orders of leaflets and lobes; ultimate lobes elliptic, 1.5 times or more longer than wide, margins incised, apex subapiculate. Inflorescences racemose, 10-20(-30)-flowered, primary racemes shorter than to slightly exceeding leaves, secondary racemes fewer flowered; bracts elliptic to linear, 4-10 × 1-2 mm, rarely larger, margins often denticulate toward apex, distal bracts usually much reduced. Flowers at first erect, later reflexed; pedicel 5-10 mm; sepals ovate to attenuate-ovate, to 1-3 mm, margins often sinuate or dentate; petals pale to bright yellow; spurred petal 13-16 mm, spur straight or slightly incurved, 4-5 mm, apex subglobose, crest low and incised or absent, marginal wing moderately to well developed, unspurred outer petal 9-11 mm, crest same as that of spurred petal; inner petals oblanceolate, 8-10 mm, blade wider than claw and more prominently winged toward apex, claw 3.5-4.5 mm; nectariferous spur 2-3 mm; style ca. 3 mm; stigma 2-lobed, 1/2 as long as wide, with 8 papillae. Capsules erect to pendent at maturity, linear, often torulose, slender to somewhat stout, straight to moderately incurved, 12-24(-30) mm. Seeds nearly 2 mm diam., appearing essentially smooth under magnification, narrow marginal ring present or absent. The Navaho used Corydalis aurea medicinally for a variety of ailments, including rheumatism, diarrhea, sores on the hands, stomachaches, menstrual problems, and sore throats, and as a general disinfectant (D. E. Moerman 1986, no subspecies cited).
Prostrate-ascending annual or biennial, 2-5 dm, the stems sympodial; racemes dense, 1-3 cm, often surpassed by the upper lvs; bracts lanceolate; sep broadly ovate, 1.5-2 mm, erose; cor bright yellow, 13-16 mm, incl. the 4-5 mm spur; outer pet folded distally along the median line into a conspicuous but wingless keel; fr smooth, spreading or drooping, 1.5-2.5 cm; seeds ca 2 mm wide, with a narrow ring-margin; 2n=16. Rocky banks or sandy soil; Que. to Alas., s. to Pa., Mich., n. Ill., and Minn., and widespread in w. U.S. May-July. Our plants are var. aurea; var. occidentalis Engelm., often attr. to our range (as C. montana Engelm.) is more southwestern.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.