Biennial or more often perennial, 3-10 dm, villous in the infl; cauline lvs narrowly oblong, sessile, entire or nearly so, glabrous beneath; sep lanceolate, densely villous,
7-10 mm; cor white to pale yellow 2-3 cm, the tube strongly inflated, veined with brown or violet, the lower median lobe prolonged, 8-13 mm, much surpassing the lateral ones; 2n=56. Native of s. Europe, rarely escaped from cult. in our range. Summer. Produces a variant form of digitalis.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.