Stems 2-6 dm, villous; cauline lvs 2-3 pairs, broadly cordate- ovate, 4-8 cm, coarsely toothed, sparsely hairy, the petiole often longer than the blade; lowest pair of bracteal lvs resembling the foliage lvs and scarcely smaller, but sessile, the upper ones progressively reduced; cal 8-10 mm, the lobes slightly shorter than the tube; cor pale greenish-yellow or greenish-white, 3-3.5 cm, the lower lip with purple lines. Rich woods; w. Va., s. O., s. Ind., and s. Ill., s. to e. Tenn. and n. Ala. May-July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.