Erect perennial 3-10 dm, the angular stem often bristly above; lvs short-bristly, coarsely and irregularly serrate, the lower on long petioles, cordate or triangular, the upper narrower but scarcely shorter, lanceolate, narrowed to a very short petiole; fls in loose terminal or axillary clusters; hypanthium and lanceolate sep (10-13 mm) bristly with pale hairs; cor blue or violet, campanulate, 2.5-4 cm; 2n=34. Native of Eurasia and n. Afr., intr. in waste places and along roadsides from Que. to Mass. and O. Aug.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.