Rhizome creeping; terminal part of stem erect, 30-50 cm tall; cataphylls and prophylls linear-lanceolate, 15-16 × ca. 2.5 cm. Petiole 25-40 cm, proximal part with 2-5 mm wide sheath; leaf blade sagittate-cordate, 15-30 × (8-)15-28 cm or usually more; primary veins 7 per side, 2-4 of these basal, downward to basal lobes and then arching into leaf margin, secondary and tertiary ones thinner, numerous. Inflorescences 1-3 together; peduncle shorter than petioles, 10-15 cm. Spathe pale green, oblong or elliptic, 5-6.5 × 3-3.2 cm, fusiform before anthesis, distal part slightly spreading and shortly boat-shaped at anthesis, 5-6 cm wide when spread out completely, apex with a beak ca. 1 cm. Spadix sessile or shortly stipitate, 3-5 cm; female zone 1-1.5 cm × 4-5 mm; ovary oblong, 3-loculed, with 1 staminode at side of base; ovules numerous; placentation axile; stigma disciform; male zone 2-3 cm × 3-4 mm. Seeds brown, oblong. Fl. Jul-Sep.