Robust twining perennial herb with stems up to 10 m long. Stems and petioles, hairless covered in small spine-like reddish-brown tubercles; older stems becoming woody. Leaves up to 13 cm in diameter, deeply palmately or pedately 7-9-lobed, lobes often pinnately lobed again, hairless. Flowers solitary or in few-flowered axillary clusters on a long peduncle, up to 8 cm. Corolla funnel-shaped, 6-8 cm in diameter, whitish to pale yellow with a dark purple centre.