Plants rhizomatous; rhizomes brownish, unbranched or highly branched, linear to irregularly contorted, 0.5–1.5 cm or more diam., nodes not articulate. Stems longitudinally grooved or sometimes narrowly winged, usually terete in cross section, 1–7 m, ± rigid proximally, or flexible, glabrous or rarely with sparse pubescence, wings when present less than 1 mm and stems polygonal. Leaves alternate, subopposite, subverticillate, or in verticels of 3–7 proximally, due to suppression of proximal inter-nodes (esp. in woodland understory), always alternate distally, 3–13 × 2–13 cm, ca. as long as wide; petiole ridged or narrowly winged, 3–14 cm, glabrous or puberulent at pulvinus, base not clasping; blade green to ± glaucous, (7–)9–11-veined, ovate-cordate, abaxial surface sometimes ± glandular, or sparsely or sometimes densely pubescent to glabrous, base with sinus rounded, acute, or ± truncate basally, margins entire or repand, apex acute to acuminate, occasionally mucronate. Staminate inflorescences solitary in leaf axils, rarely terminal, spicate or branched; cymes sessile, bearing 1–3 sessile flowers, braceolate, internodes between cymes 1–8 mm, bracteoles ca. 1 mm; rachis 2–30 cm, secondary axes to 15 cm, robust plants occasionally branched to third order, axes subtended by linear-lanceolate bracts 1–3 mm. Pistillate inflorescences solitary, 4–18-flowered, 4–20 cm, internodes 6–12 mm. Staminate flowers: perianth greenish white, appearing darker in some specimens due to presence of irregularly distributed tannin crystals, rotate-campanulate to funnelform, 1–2(–3) mm diam.; tepals ± glandular, ovate-elliptic, margins hyaline, apex rounded or acute; stamens in 2 subequal whorls, erect; anthers ca. ½ length of filaments, thecae distinct, widely spreading. Pistillate flowers: perianth greenish white, rotate-campanulate, 2–4 mm wide; tepals as in staminate flowers; staminodes 6, differentiated into anthers and filaments, less than 1/2 length of fertile stamens. Capsules greenish gold, ovoid to obovoid to obreniform, 1–3 × 1–3.5 cm, varying continously in size, occasionally ± glaucous. Seeds generally 2 per locule, rarely 1, 5–18 mm. 2n = 20, 36, 54, 60.
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Rhizomes relatively slender; stems twining counterclockwise, to 5 m, usually glabrous; lvs all or nearly all alternate, the blades glabrous or hairy beneath, cordate-ovate, abruptly acuminate, 5–10 cm, 7–11-nerved; staminate infl widely branched, with 1–4 fls per node; pistillate spikes 5–10 cm, with solitary fls; ovary fusiform, 5–7 mm; fr 16–26 mm, each of the 3 thin valves semi-orbicular or half-ovate; seeds 8–18 mm; 2n=60. Moist open woods, thickets, and roadsides; Conn. and N.Y. to Minn., s. to Fla. and Tex. June, July. Some coastal-plain plants with hairy stem and relatively few-fld infls have been segregated as var. hirticaulis (Bartlett) Ahles. (D. hirticaulis)
A climbing yam plant. It can be 5 m tall. It keeps growing from year to year. It has slender rhizomes. They are twisted, long and woody. The leaves are simple. The stem has bulbils in the axils of leaves. The leaves are heart shaped and 5-10 cm long. The flowers are small and yellow-green. The are in drooping spikes in the axils of leaves. Male and female flowers are borne separately. The fruit is a capsule that in longer than wide. The seeds are winged at the base.
Borders of bogs, swamps, marshes, river and lake margins, creek bottoms, sandy or rocky soils, moist or dry woods, hammocks, thickets, limestone or talus slopes, roadsides, sea level to 1500 m.
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It is a temperate plant. It is best in rich, moist soils. It needs a protected sunny position. It is resistant to frost but damaged by drought. In Assam is grows up to 1,600 m above sea level.
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