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.
There is a colony of what I think is this species in the talus of a west slope of the cliff along Blue River about half a mile north of Whitecloud, Harrison County. It has been reported from four of the northern counties but I am referring these reports to the variety [var. intonsus]. [Deam calls densely pubescent plants var. intonsus. They are] infrequent to very rare in some of the counties of the lake area where it is generally found in dry, sandy soil in open, black oak woods, in prairie habitats, and rarely in a marshy habitat. I have had this variety under cultivation for a few years and it is spreading rapidly by underground stems. There have been four reports for the species from the northern counties but I am referring them all to the variety.