Simple, 3-6 dm; lvs 3-5 pairs, lance-ovate, 5-8 cm, acute or obtuse and mucronate, rounded to the sessile base, scabrous-ciliolate, otherwise glabrous; umbel solitary, terminal, few-fld; peduncle 5-15 cm; cor greenish-white, its lobes 8-10 mm; hoods purple, much distended at base; 5-7 mm, the lateral margins with an obtuse tooth near the middle; horns subulate, incurved, shorter than the hood. Prairies; originally from c. Ill. and c. Mo. to e. Kans., with outlying sites in ne. Ind., s. Wis., and se. Io.; now rare and restricted to Ill., Mo., and Kans. June, July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.