Stems slender, 3-5 dm, often decumbent at base, usually glabrous; lvs few, seldom more than 4 pairs below the infl at anthesis, with a few lfless nodes near the base, the lower lvs narrowly lanceolate and long-petioled, the upper broader and becoming sessile, the larger ones 6-10 cm; sterile basal shoots often present, with lance-oblong, long-petioled lvs tapering to both ends; infl a few small cymes forming a rounded or flattened corymb; pedicels glabrous or minutely glandular-hairy; cal 10-13 mm; glabrous or sparingly villosulous; cor red-purple, 2.5-3 cm wide; style elongate; 2n=14. Open woods and thickets, chiefly in the mts.; Pa. to n. Ga., also in O. and Ind. May, June. (P. latifolia)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.