Stem mostly simple, 4-9 dm, roughly short-hairy; lower lvs lanceolate, 5-10 cm, acuminate, coarsely few-toothed, very scabrous, the upper progressively smaller and narrower; spikes peduncled, elongating in fr to 1-2 dm; cal hairy, 6-9 mm, much surpassing the subulate bracts; cor deep purple, the tube 1-1.5 cm, the lobes 5-8 mm; fr 6-8 mm, barely surpassing the persistent cal; 2n=42. Sandy or gravelly soil of upland woods or prairies; N.Y. and s. Ont. to Mich., Ill., and se. Kans., s. to Ga. and Tex. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.