Stems erect, 1-2 dm, often several from the end of a moniliform rhizome, minutely pubescent on the angles with eglandular curved-ascending hairs; main cauline lvs sessile, lance-ovate or somewhat deltoid, 10-16 mm, 2-3 times as long as wide, entire, glabrous, or somewhat scabrous above, especially near the tip and margin, the lateral veins 1 or commonly 2 on each side of the midrib, not anastomosing; fls axillary, 7-9 mm, the short pedicels with curved-ascending hairs; cal not glandular, lower lip of the cor hirtellous in 2 lines. Dry upland woods and prairies; Mass. to Mich. and N.D., s. to Va., Tenn., Ark., and Okla., most abundant in the Middle West. May-July. (S. ambigua, misapplied)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.