Plants perennial, 4.5-6(-13) dm; rhizomatous. Stems ribbed, gla-brous or strigose. Leaves: ocrea brownish hyaline, cylindric, 10-20 mm, base inflated or not, margins truncate, ciliate with bristles 0.5-4 mm, surface strigose to tomentose; petiole (0.1-)1-2 cm, leaves sometimes sessile; blade 5-17.5 × 2-10 cm, apex acute to acuminate, faces pubescent abaxially, strigose and scabrous adaxially. Inflorescences (50-)100-350 × 7-15 mm; peduncle 10-70 mm, pubescent or glabrous distally; ocreolae not overlapping, margins ciliate with bristles to 3 mm. Pedicels ascending to spreading, 0.5-1 mm. Flowers 1-3 per ocreate fascicle; perianth white, greenish white, or rarely pink, glabrous, accrescent; tepals elliptic to obovate, 2.5-3.5 mm, apex acute to acuminate; filaments distinct, outer ones sometimes adnate to perianth tube; anthers yellow or pink, ovate; styles distinct. Achenes included except for apex and styles, brown to dark brown, biconvex, 3.5-4 × 2-2.8 mm, dull to shiny, smooth to rugose. 2n = 44. Flowering Jul-Oct. Rich deciduous forests, floodplain forests, dry woodlands, thickets; 0-500 m; Ont., Que.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va., Wis.; c Mexico. Tension in the articulation of the pedicels is sufficient to throw mature achenes 3-4 m when the inflorescence is bumped, and the persistent, hooked styles aid in the dispersal of achenes in the fur of animals (H. S. Reed and I. Smoot 1906). A hot infusion of leaves with bark of honey-locust (Gleditsia triacanthos Linnaeus) was used by the Cherokee to treat whooping cough (D. E. Moerman 1998).
From Flora of Indiana (1940) by Charles C. Deam
This is strictly a woodland species and is frequent throughout the state in low places in almost all types of woods.
Erect, rhizomatous perennial 5-10 dm; lvs lanceolate to ovate, to 15 cm, acuminate, rough-hairy to glabrous; petioles to 2 cm; ocreae pubescent and long-ciliate; racemes very slender, terminal, 1-4 dm, the ocreolae well separated below, becoming contiguous or overlapping upwards, 1-3-fld; pedicels divergent, jointed at the summit; tep 4, greenish-white or suffused with pink, 2.5 mm, the 2 lateral ones external and somewhat smaller than the median ones, scarcely changed in fr; achene lenticular, ovate, 4 mm; styles 2, persistent, indurate, deflexed, connivent, hooked at the tip; 2n=44. Moist woods; N.H. to Minn. and Nebr., s. to Fla. and Tex. (Antenoron v.; Tovara v.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.