Rhizomatous perennial 3-6 dm, the stems usually forked, with ascending branches; pubescence of the younger stems, the petioles, and often also the pedicels, consisting wholly or in considerable part of short, stiff, ±decurved hairs; lvs ovate to narrowly lanceolate, acute, sinuately toothed to entire, narrowed to the base and ±decurrent on the long petiole, sparsely to abundantly hirsutulous on both sides, minutely ciliolate; pedicels at anthesis 1-2 cm, not much elongating in fr; cal hirsute or hirsutulous with spreading hairs, its lobes at anthesis 2.5-5 mm, densely ciliolate; cor 12-18 mm, yellow, blotched within, filaments dilated below, gradually narrowed above; anthers 2-3 mm; fruiting calyx sunken at base, 5-angled, notably longer than thick; fr orange; 2n=24. Fields, upland woods, and prairies; Conn. to Mich., Minn., and Colo., s. to S.C., Ala., and Ariz. (P. monticola)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.