Infrequent but usually in colonies where it is found. In southern Indiana it is found on the crests of chestnut oak and black oak ridges and on sandstone outcrops. In northern Indiana it is found in very dry, sandy soil on black oak land and was formerly common on the low dunes about Lake Michigan. It is also found on sandy hills in the open or in open woodland in northwestern and southwestern Indiana. The habitats of the species and the [pubescent var. holosericea] are the same and it is probable that their range is co-extensive. My attention had not been called to the variety before I undertook to write the genus. Since I usually collect only one specimen from a county, the maps do not accurately represent the distribution of the two forms.
Stems 1-several, ±erect, 2-7 dm, unbranched or with a few weak axillary branches; herbage densely villous or sericeous to sparsely strigillose or partly glabrous; lfls mostly (9-)15-25(-31), elliptic or linear-oblong, 1-3 cm; racemes terminal to the main stem and sometimes to axillary branches, short-pedunculate or sessile, compact, mostly 4-8 cm; pedicels 4-10(-17) mm; bracts setaceous, deciduous; fls 1.5-2 cm, usually bicolored, the standard yellow to ochroleucous, the wings and keel pink or pale purple; fr 3.5-5.5 cm, strigose to villous; 2n=22. Old fields, open woods, and dunes, often in sandy soil; s. N.H. to Fla., w. to Wis., se. Minn., Kans., and Tex. June, July (Cracca v.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.