Infrequent in its habitat throughout the state and usually only a few plants found at a place. It is most commonly found in sandy soil in prairie habitats and in thin oak woods. It is also found in hard, clay soil or gravelly soil on white oak slopes, in hard, white clay of the "flats" of the southern counties, and once I found it on a bar in the Wabash River.
Plants 1-2 m, widely branched, glabrous and glaucous; stipules lanceolate, 5-10 mm, some usually persisting until anthesis; petioles 6-12 mm; lfls narrowly obovate to oblanceolate, 3-6 cm; racemes solitary or few, erect, 2-6 dm; bracts lance-ovate, caducous; pedicels 4-10 mm; fls white or with a tinge of purple on the standard, 18-25 mm; cal 8 mm, densely pubescent within; pods black, drooping, ellipsoid-oblong, firm and thick-walled, 2.5-4 cm נ8-12 mm, abruptly narrowed to a short beak; stipe well exserted; 2n=18. Prairies and open upland woods; O. and s. Mich. to Minn., Neb., and Tex., and e. in the coastal states to Fla. and N.C.; locally (intr.?) in w. N.Y. June, July. Ours is var. lactea. (B. leucantha)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.