Annual; lvs ovate to oblong or broadly elliptic, 3-8 cm; fls 3-6+ cm, violet or red to white or particolored; 2n=14, 28. Occasionally escaped from cult., but not persistent. Some forms of this cultigen approach one or the other of the original parents: P. axillaris (Lam.) Britton, Sterns & Poggenb., with white fls, the cor-tube 4-6 cm, only slightly expanded upwards, the anthers inserted near the middle of the tube and extending nearly to its throat; and P. integrifolia (Hook.) Schinz & Thell. (P. violacea), with purple or violet fls, the cor-tube 3 cm, conspicuously expanded from base to summit, the stamens inserted near the base and extending barely past the middle of the tube.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.