Annual herb with prostrate or climbing stems up to 3 m long, with spreading bristly hairs. Leaves broadly ovate in outline, up to 10 × 12.5 cm, usually deeply 3-7 lobed, with bristly hairs on both surfaces, becoming roughly puntate; margin finely sinuate-denticulate; petiole 2-12 cm long, with long spreading bristly hairs. Flowers unisexual on the same plant, yellow. Male flowers in 2-10-flowered axillary clusters, c. 1.4 cm in diameter; female flowers solitary, c. 2 cm in diameter, sometimes in the same cluster as male flowers. Fruits subglobose or ellipsoid, up to 4.5 × 3.5 cm covered in soft spines, green, sometimes with pales stripes, turning pale yellow when ripe; fruit stalk 5-21 cm long, somewhat expanded upwards.