Stems ascending, to 10(-20) dm; herbage rough-pubescent to hirsute, often with simple hairs, those around the base of the cal stiff, spreading, 1-3 mm; lvs orbicular in general outline, deeply 5-7-lobed, the principal divisions oblanceolate to cuneate-obovate, lobed or incised; stipules mostly 5-15 mm; peduncles (pedicels) mainly axillary, 3-10 cm, 1-fld; bractlets lanceolate or linear, 8-17 mm; gynodioecious; cal-lobes lanceolate or lance- ovate, 9-16 mm, with separate, loose, free tips 4.5-10+ mm, pet red or purple with a white basal spot, 19-32 mm (9-20 in functionally pistillate fls); mature carpels strongly rugose, strigose at least distally; 2n mostly=30, 60. Open places, esp. dry upland prairies; Ill. to s. Minn. and w. Wyo., s. to Ark., Tex., and n. Mex.; adventive in Pa. May-Oct. Our plants belong to the northern var. involucrata, as here described.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.