Climber to 15 m. Rhizome c. 0.5–2 cm in diam., branching and spreading horizontally, shallowly buried, periderm not hard and lacking rigid, spine-like roots. Indumentum of fine, white, simple hairs, 0.15–0.6 mm long, usually dense on young shoots, leaves (epecially dense on veins of lower surface towards base) and inflorescences (all parts pubescent except inner whorl tepals), vegetative organs glabrescent. Stems 2–5 mm in diam., twining to the left, annual, often spiny toward base, unarmed on upper stem, terete. Leaves simple, alternate, blades ovate to broadly ovate, margins of vegetative shoot leaves often shallowly 3–5 lobed, sometimes irregularly so or more deeply, occasionally entire, fertile shoot leaves usually entire, blade thinly to very thinly chartaceous, dark green to yellow-green above, paler and pubescent below, 7–9-veined, base often cordate but sometimes obtuse or rounded on reproductive shoots, apices acute to acuminate; petioles (1.5–)3.3–6.5(–12) cm long; lateral nodal spines 0.5–3.3 mm long, straight or curved; cataphylls and bulbils absent. Inflorescences pendent, axes finely tuberculate, tepals fused at base, erect to spreading, apices recurved, inserted on a cup-shaped torus; male inflorescences usually compound, 1(–2) per axil, partial inflorescences 1 per node, racemose with a cymule of 1–3 flowers on a short branch at each node, peduncles 0.3–2 cm long, axes 2–10 cm long; female inflorescences simple, spicate, 1 per axil. Male flowers 2– 3.3 mm in diam. at anthesis, pedicels 0.8–1.2 mm long, outer tepals 1.9–2 by 1.0–1.7 mm, ovate to ovate-oblong, inner tepals 1.9–2.1 by 0.4–0.6 mm, stamens 6. Capsules 18–25 by 18–40 mm. Seeds 3.5–4 by 5–6 mm, ovoid to lenticular, wings 16–18 by 13–14 mm, extending all around seed margin.