Perigynium 1.2-1.5(-1.7) mm wide; stems usually smooth; ventral face of sheath of upper cauline lf shallowly to more often deeply concave, its cleft often extending more than 1 mm (to 2.3 mm) below the junction with the blade; 2n=36. Upland woods in e. U.S., widespread with us.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.