male flowers usually 2–6 in short fascicles at the nodes on leafless stems, less often solitary and sometimes axillary to the foliage leaves; pedicels 1–7·5 cm. long, finely pubescent. Receptacle-tube 2·5–7 mm. long, lobes 3–12·5 × 1–2·5 mm., lanceolate, acute, often acuminate, finely pubescent. Petals 1·8–3·5 × 1·4–2·5 cm., deep cream to orange-yellow, rarely white, obovate, rounded, apiculate. Anther thecae minutely hairy.
Leaf-lamina 2·5–12 × 1·5–12 cm., bright green, membraneous, ovate to broadly ovate in outline, cordate, more or less asperulous or puberulous especially on the veins beneath, unlobed or usually and often deeply palmately 3–5-lobed; lobes broadly triangular or ovate to narrowly elliptic or linear, sometimes lobulate, entire or ± sinuate-dentate, apiculate, the central largest.
Female flowers solitary; peduncles 4–10 mm. long; ovary 6–22 × 0·5–2·5 mm., shortly pubescent; receptacle-tube 1·5–5 mm. long, campanulate, lobes 3–4·5 mm. long, lanceolate or lanceolate-subulate; petals 2·4–3·2 × 1·1–2·0 cm.
Stems annual, trailing or climbing to 3 m., finely pubescent; old basal stems arising from tuber becoming thickened, gnarled, with pallid papyraceous bark.
Fruit 4·5–8·5 × 2·4–3·5 cm., ellipsoid or cylindrical, rostrate, terete; fruit-stalk stout, 0·5–2·5 cm. long.
Seeds 6·5–10·2 × 6–7·5 × 4·5–6·2 mm., subpisiform, smooth.
Tuber subterranean, napiform, rough-barked.
Petioles 1-3 cm. long, shortly pubescent.
Slender scandent herb.