Staminate plants 5-20-leaved, 1.5-3.5 dm. Pistillate plants 15-50-leaved, 3-6 dm, 1.5 m in fruit. Leaf blades spatulate to oblanceolate, 5-20 × 1.5-6 cm, apex obtuse, tapering proximally to broad petiole, 4-6 cm; distal blades oblanceolate to linear, 3-8 × 1-1.5 cm. Staminate flowers divergent, white; tepals 3-4 mm; filaments dimorphic, the outer longer; anthers white, 0.5 mm; pistils absent; pedicel 2-5 mm. Pistillate flowers ascending, white; tepals 2-3 mm; staminodes present; ovary elliptic to obovate; styles 1.5-2 mm; stigmas sessile. Capsules ovoid-oblong, 7-14 × 5-6 mm. Seeds reddish brown, 1.8-2 mm; 5-6 mm (including winglike aril). Flowering late spring--summer. Moist meadows, thickets, rich wooded slopes, and coves; 0--1100 m; Ont.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., La., Md., Mass., Mich., Miss., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Va., W.Va.
From Flora of Indiana (1940) by Charles C. Deam
I found a single plant in an exposed place on a limestone slope 3 miles north of Milltown, Crawford County where it was associated with Comandra richardsiana and Lithospermum croceum. I found another specimen in a woods about 7 miles southwest of Evansville where it was closely associated with Fagus grandifolia, Quercus alba, Cornus florida, Sassafras albidum and Phytolacca americana. In both instances I found only a single specimen although I made extended search for others. Clapp reported it from the barrens near New Albany, and Barnes reported it from Jefferson County without comment. The distribution of this species is erratic and observers do not seem to understand what factors are involved. It has been reported from 15 counties in Ohio but northward it has not been reported until the Upper Peninsula of Michigan is reached.
Staminate plant 3-7 dm, the pistillate taller, to 12 dm; basal lvs elongate-spatulate to obovate, 8-15 cm; the cauline progressively smaller and narrower, the upper linear; fls white, drying yellowish, the tep 3 mm; staminate spike 4-12 cm נ10-15 mm, with spreading pedicels; pistillate spike very slender, to 3 dm, the pedicels erect or ascending; fr ellipsoid or somewhat obovoid, 7-14 mm; seeds 3-5 mm. Moist woods and bogs; Mass. to Fla., w. to s. Ont., O., s. Ind., s. Ill., Ark., and La. June. (C. obovale)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.