Plants 3-6 dm; petioles 0.5-2 cm; lf-blades 8-10 cm; peduncles 4-10 cm; bracts linear or lf-like, 3-15 mm; bractlets 3-8 mm; rays 2-4, 5-15 mm, unequal; pedicels 2-8,to 1 mm; sep to 1 mm; fr 8-10 mm; 2n=18. Moist low ground; S.C. to Miss., and up the Mississippi embayment to w. Ky.; rare. May, June.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.