Stems slender, erect, 5-12 dm, usually glabrous; lvs numerous, firm, spreading, linear to narrowly lanceolate or sometimes even ovate, gradually tapering to a sharp tip, 5-12(-15) cm נ3-15(-20) mm; infl usually of several cymes, terminal and from the upper 1-4 pairs of axils, the lower on long peduncles; cal 5-10 mm; cor red-purple, 1.5-2 cm wide; style elongate; 2n=14. Wet woods and open prairies; Md. to O. and s. Wis., s. to S.C., Ga., Ala., and Ark. June, July. Variable, but the infraspecific taxa, if any, not yet clear. (P. triflora; P. carolina, at least as to plants from our range)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.