Much branched, 1-4 dm from a tuberous- thickened root, conspicuously spreading-hairy; petioles of at least the larger lvs mostly (3-)4-10 cm; lfls 5, oblong to oblanceolate or narrowly obovate, 2-6 cm; spikes dense, leafy-bracteate, 3-8 cm; fls blue, sessile or nearly so, 15-20 mm; cal-tube gibbous, 5-6.5 mm, glabrous or sparsely hirsute, the lobes subequal, lance-linear, 7-10 mm, ciliate; fr hirsute, the flat beak evidently longer than the body; 2n=22. Dry prairies and plains; Minn. and Wis. to Mo. and Tex., w. to Alta. and N.M. May-July. (Psoralea e.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.