Stems 2-5 dm, finely puberulent below with minute reflexed hairs, often in 2 strips, or glabrous; cauline lvs lanceolate to lance-linear, glabrous or less often finely hairy; infl glandular-pubescent, slender, the short lateral branches erect; cal 4-6 mm at anthesis; cor 1.5-2.2 cm, pale violet; seeds 0.6-0.8 mm; 2n=16. Prairies and open woods; Wis. to Man. and Alta., s. to Io., Nebr., and N.M. June, July. (P. wisconsinensis, the phase with puberulent lvs)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.