Herbs, perennial, 3-10 dm, stoloniferous. Stems erect, largely simple proximal to inflorescences, villous or glabrous. Leaves op-posite; blade ovate to elliptic, 6-15 × 2-7 cm, apex acute to long acuminate, sparsely pubescent. Inflorescences: panicles 7-30 cm; bracts and bracteoles of staminate and pistillate flowers shorter than tepals. Flowers: tepals white, ovate, 1-1.3 mm, hyaline, apex acute to acuminate, densely lanate. Utricles exerted from tepals, greenish white, ovoid, 1.1-1.5 mm, apex rounded. Seeds 0.5-0.8 mm.
"Dioecious, rhizomatous perennial 5–15 dm, pilose at the nodes; lvs thin, bright green, lance-ovate, acuminate, entire, to 14 cm, a third to half as wide; panicles terminal and from the upper axils, pyramidal, 1–3 dm, with innumerable tiny fls; bracts and bracteoles ovate, shorter than the cal; sep lance-ovate, 1.2–1.5 mm, those of the pistillate fls subtended by long (eventually 3–5 mm) hairs; fr rotund, 2–2.5 mm. Damp woods; Md. to Va. and Ala., w. to Kans. and Tex. Aug.–Oct. (I. paniculata, misapplied)"