Biennial; stems 10-15 dm, finely hairy; lvs lance-ovate to ovate, toothed, those subtending the verticils smaller, proportionately narrower, few- toothed to entire; bracts half as long to longer than the inconspicuously 10-nerved cal-tube; cor 5-7 mm, scarcely surpassing the cal, without an internal ring of hairs; 2n=24. Native of Europe and n. Asia, intr. in waste places here and there in our range. June-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.