Taprooted perennial; 3-10 dm, branched above, finely and densely canescent throughout; lvs all cauline, triangular-ovate, cordate or truncate at base, 3-8 cm, coarsely toothed, the petiole half as long as the blade; fl-clusters 2-6 cm, continuous or interrupted, rather loosely many-fld; cal at anthesis 5-7 mm, weakly bilabiate, the lobes half as long as the tube; cor 8-12 mm, dull white, dotted with pink or purple, the lower lip crenulate; 2n=32, 34, 36. Native of Eurasia, now established in disturbed habitats throughout our range and w. July-Oct.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.