Biennial or short-lived perennial, glabrous and glaucous throughout, to 2 m; lvs entire, the lower obovate-oblong, 2-4 cm wide, the upper progressively shorter but scarcely narrower, becoming broadly ovate to rotund, subcordate and somewhat clasping; bracteal lvs similar but smaller; fls 2-4 per axil, short-pediceled in a racemiform infl 1.5-3 dm; cal at anthesis 7-11 mm; cor 3.5-5 cm, pale purple outside, glabrous inside and out, widely dilated; fr 1.5-2 cm; seeds 2.5-4 mm; 2n=16. Dry prairies and barrens; Wis. to N.D. and Wyo., s. to Ill., nw. Mo., and Tex. May, June. (P. bradburyi)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.