7. Corydalis crystallina (Torrey & A. Gray) A. Gray, Manual ed. 5. 62. 1867; Bot. Gaz. 11: 189. 1886.
Corydalis aurea Willdenow var. (ß) crystallina Torrey & A. Gray, Fl. N. Amer. 1: 665. 1840
Plants winter annual, glaucous, from somewhat succulent roots. Stems 1-several, erect or ascending, 2-4 dm. Leaves compound; blade with 2 orders of leaflets and lobes; ultimate lobes lanceolate to linear-lanceolate, margins incised, apex subapiculate. Inflorescences racemose, (8-)12-15(-18)-flowered, primary racemes exceeding leaves, later secondary racemes fewer flowered, exceeded by leaves; bracts ovate to ovate-acuminate, 5-12 × 3-6 mm, distal usually much reduced. Flowers erect; pedicel stout, ca. 1 mm; sepals broadly ovate to cordate, somewhat attenuate, to 2 mm, margins sometimes incised; petals bright yellow; spurred petal 16-22 mm, spur straight, 6-8 mm, apex distinctly globose, crest very high, wrinkled or toothed, marginal wing very broad, revolute, unspurred outer petal 12-14 mm, marginal wing broad, not revolute, enclosing margins of spurred petal in bud; inner petals oblanceolate, 9-11 mm, blade apex ca. 2 times wider than base, basal lobes small, claw narrow, 4-5 mm; nectariferous spur clavate, 3.5-5 mm, curved near apex; style slender, ca. 4 mm; stigma wider than long, with 8 papillae. Capsules erect, linear, stout, straight to slightly incurved, 14-18 mm, with numerous basally pustulate whitish hairs or rarely glabrate. Seeds ca. 2 mm diam., minutely decorated, marginal ring absent.
Flowering mid-late spring. Prairies, fields, open woods, and wasteland; 10-500 m; Ark., Kans., Mo., Okla., Tex.
The peculiar pubescence of the capsules distinguishes Corydalis crystallina from all others in the genus. Also, the crest and marginal wing of the spurred petal are more highly developed than in any other yellow-flowered species.