Stout, rhizomatous perennial to 1 m; stipules narrow, semisagittate; lfls 8-12, elliptic, 3-6 cm; peduncles stout, shorter than to equaling the subtending lf, with a dense raceme of purple fls 12-20 mm; cal distinctly oblique, the lower teeth much exceeding the upper but shorter than the tube; 2n=28. Woods and thickets. June, July. Var. venosus, with the cal and herbage glabrous or nearly so, or the stems slightly hairy, occurs mostly in the mts. from e. Pa. and adj. N.J. to e. W.Va. and Ga. Var. intonsus Butters & H. St. John, with the cal and herbage sparsely to densely hairy, occurs from s. Ont. to Minn. and Sask., s. to Ind. and Mo., as well as in the range of var. venosus and at one station in e. Que.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.