A twining or scrambling, urticating perennial herb, monoecious; stems up to 3 m long; indumentum a mixture of short soft hairs, longer stiffer hairs and stinging bristles.Stipules 4–7.5 mm long, linear-lanceolate, membranous, sparingly pubescent without, glabrous within, green.Petioles 0.5–8 cm long, indumentum similar to that of the stems.Leaf blades 3–14 × 1.5–8 cm, elliptic-ovate to oblong-lanceolate or lanceolate, shortly acutely acuminate at the apex, closely and sharply patent serrate with rounded sinuses or sharply patent biserrate with rounded sinuses, truncate to cordate at the base, membranaceous, 5–7(9)-nerved from the base, sparingly to evenly puberulous and weakly hispid on the upper surface, evenly to densely pubescent beneath, and setose along the midrib and main nerves on both surfaces; lateral nerves in 3–5 pairs, not or scarcely prominent above or beneath.Inflorescences 2–5.5 cm long, the peduncle 1–3 cm long, ± laxly few-flowered; male bracts 2–3 mm long, patent-reflexed, oblanceolate-oblong to subspathulate, entire or subentire, pubescent; male bracteoles 1.5 mm long, linear-oblanceolate, very fugacious; female bracts 4–6 × 6–8 mm, rhombic-ovate to transversely ovate, serrate or dentate, pubescent; female bracteoles 2, 5 mm long, linear to linear-oblanceolate, pubescent.Male flowers: pedicels 2 mm long; buds subglobose; calyx tube constricted; calyx lobes 1 × 1–1.5 mm, broadly ovate, pubescent without, glabrous within, pale greenish-yellow; stamens less than 1 mm long; pistillode minute, depressed-hemispherical.Female flowers: pedicels 1 mm long, 2 mm long in fruit, densely pubescent; calyx lobes 6, 2 × 1 mm, accrescent to 8 × 3 mm, pinnatifid, with 11–21 lobules, the terminal lobule lanceolate, the lateral lobules subulate, ± equalling the width of the calyx-lobe rhachis, hispid and setose, greenish, the calyx-lobe rhachis narrowly loriform, sparingly pubescent without, glabrous within, yellowish green, becoming hardened and stramineous within; ovary 1.5–2 mm in diameter, 3-lobed, densely appressed-pubescent, setose on the keels; stylar column 3 mm high, infundibuliform, appressed-pubescent, stigmas short, granulate, recurved.Fruit 4.5 × 7 mm, deeply 3-lobed, smooth, evenly appressed-pubescent and hispid, setose on the keels.Seeds 3 mm in diameter, globose, dark grey with whitish wavy lines, and spotted, flecked and mottled with dark purplish-brown.