Much branched, 3-10 dm from a tuberous-thickened root; petioles under 1 cm, equaling or shorter than the well developed petiolules; lower lvs 3-foliolate, the upper often 1-foliolate; lfls elliptic to obovate, 2-5 cm, blunt or rounded, gray-villous beneath; fls blue, 11-14 mm; cal very gibbous at base, thinly villous, glandular-punctate, the tube 3-4 mm, the 4 upper lobes 3.5-4.5 mm, the lowest one 5-6 mm. Dry, sandy soil; se. Va. to Fla. and Ala. (Psoralea c.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.