Herbs, annual, 3–5 dm, monoecious. Stems erect, sparsely pubescent. Leaves: petiole 1–7 cm; blade ovate, 2.5–10 × 1.5–8 cm, base broadly obtuse to rounded or truncate, margins serrate, apex acuminate. Inflorescences unisexual, axillary (staminate) and terminal (pistillate; sometimes on short lateral branches, appearing axillary); staminate peduncle 0.5–0.7 cm, fertile portion 0.5–1.5 cm; pistillate peduncle 0.1–0.5 cm, fertile portion 3–12 × 0.7–1 cm; allomorphic pistillate flowers common, near apices of pistillate inflorescences and mixed with flowers in staminate inflorescences. Pistillate bracts (normal flowers) loosely arranged (inflorescence axis visible between bracts), 5–7 × 3–4 mm, abaxial surface glabrous; lobes 7–9(–13), linear, nearly bract length, muricate; of allomorphic flowers on pistillate inflorescences like those of normal flowers, on staminate inflorescences absent. Pedicels of allomorphic flowers rudimentary. Pistillate flowers: pistil 3-carpellate (normal flowers), 1(–3)-carpellate (allomorphic flowers); styles multifid or laciniate. Capsules smooth, sparsely pubescent; allomorphic fruits oblate ellipsoidal, longitudinally ridged, an irregular flange on each side, 1.4–1.7 × 1.5–2 mm, smooth, puberulent. Seeds 1.2–1.4 mm, minutely pitted.