Tuber depressed globose, 2-6 cm in diam. Cataphylls greenish or reddish, often with purple-brown marks. Leaf solitary; petiole white or pale green, usually mottled with purple-brown marks, 12-70 cm, proximal 2-30 cm sheathing into pseudostem; leaf blade radiate; leaflets 7-15, glaucous abaxially, green adaxially, oblanceolate, apex filiform, caudate, with a threadlike pendulous tail at tip. Peduncle distinctly shorter than petioles, 3-45 cm. Spathe purplish red to dark purple, with fine green dots between veins outside; tube white or pale yellowish green with purple stripes inside, obconic, gradually opening to auriculate throat, 2-6 × 3.7-8 cm; limb dark purple, ovate to broadly ovate, 3-8 × 3.5-8 cm, scarcely with pale veins on inner surface, apex acute to acuminate with a prolonged filiform tail to 40 cm. Spadix 3-10 cm including appendix, unisexual; female zone conic, 2.8-3 cm × ca. 12 mm, base narrower, with abundant aculeate neuter flowers, apex slightly enlarged, strongly rugose; male zone cylindric, ca. 4 cm × 7 mm; synandria consisting of 3 or 4 subsessile anthers; appendix sessile, whitish distally, broadly cylindric, 1.7-7 cm × 4-13 mm, strongly or weakly rugose at apex. Fl. May-Jun.