Large scandent herb. Stem up to 10 m long, 6 cm in diameter, internodes naked, ca. 1.5 cm long. Cataphylls up to 58 cm long, soon caducous. LEAVES: Petiole up to 1.04 m long, almost terete halfway, 1.9-2.5 cm in diameter, convex or flattened adaxially towards the apex, sometimes somewhat purple-spotted, sheathed part 5.7-10 cm long. Leaf blade thinly semi-coriaceous (papery when dry) nevertheless fragile, easily broken parallel to the primary lateral veins, ovate (triangular in juvenile plants), 73-90 cm long, 47-58 cm wide (6-12 cm above the base of the midrib), acute or obtuse at the apex, apex itself acuminate (0.8-2 cm), cordate-sagittate at the base; posterior lobes 19-23 cm long, 20-25 cm wide, usually angular, apex obtuse, separated by a narrowly spathulate spathe, the margins of which are almost contiguous, or the lobes are imbricate with a closed and obovate sinus; adaxially dark green, more or less glossy, midrib 1.7 cm wide, costal primary lateral veins sulcate, 5-6 on each side, emerging at an angle of ca. 55-70º, a posterior rib is naked for 0.7-2 cm in the sinus, 3 principal veins on the inner side, 3-4 outer side [of the posterior lobes]. INFLORESCENCES in pairs or threes. Peduncle 3.5-6 cm long, green, purplish at the top. Spathe 18-19 cm long, tube 9-9.5 cm long, 3-4.3 cm thick, externally at least on one side dark wine-coloured, margin diaphanous, 0.3 cm wide, blade green with wine-coloured spots; internally tube dark red-purple, blade whitish. Spadix 1.3 cm shorter than spathe, 13.3-16 cm long, sessile at the back, at the front the axis is naked for 0.8-2.7 cm; female zone yellowish, 4.9 cm long at the front, 2.8 cm long at the back, 1.7 cm thick, eventually 6.5 (4.6) cm long; sterile male zone white, 2.6-3 cm long, 2.2 cm thick; fertile male zone white 7.8 cm long, 2.2 cm thick. Pistillate flowers: ovaries 7-9-locular, numerous ovules in each locules, ('superpositus'). Male flowers 6-5(-4)-androus.