Hemiepiphytic or rarely terrestrial; stem appressed-climbing or spreading; sap viscous, unscented; internodes obtusely flattened on one side, moderately glossy, to 7 cm long, to 1.5 cm diam., usually much longer than broad, medium green to tannish, drying gray, epidermis becoming grayish brown and peeling; roots mostly 15--30 cm long, drying 2--3 mm diam.; cataphylls (8)13--16 cm long, unribbed, green, deciduous, turning mushy; LEAVES: petioles 7--16.5 cm long, (3)6--15 cm diam., D-shaped, obtusely flattened (drying usually sulcate) adaxially, more or less spongy, narrowly rounded abaxially, with adaxial margins raised, surface with a conspicuous purple-black ring around apex; sheathing usually to near the apex, with margins erect and incurled, the tip free-ending; blades more or less oblong, subcoriaceous, semiglossy, conspicuously to moderately bicolorous, abruptly long-acuminate or sometimes acute at apex (the acumen inrolled if present), rounded to weakly subcordate at base, 21--46 cm long, 5--12 cm wide (3--5 times wider than long), (ca. 2--4 times longer than petiole); upper surface semiglossy, dark green to medium green, drying dark brown to blackish brown, lower surface glossy and slightly to moderately paler; sinus 5--12 mm deep; midrib flat to broadly convex, paler than surface above, convex or thicker than broad and bluntly acute, darker than surface below; basal veins lacking; primary lateral veins weak, 4--6 per side when present but sometimes not apparent, departing midrib at a 60--70E angle, arcuate to the margins, slightly sunken, weakly visible above, convex, slightly darker than surface, weakly visible below; minor veins fine, moderately visible to distinct, arising from both the midrib and primary lateral veins. INFLORESCENCES 1 per axil; peduncle 10.5--12 cm long, 5--6(14) mm diam., subterete; spathe coriaceous, 15--18.4 cm long, (1.43--1.75 times longer than peduncle), weakly or not at all constricted, spathe blade yellow-white (B & K yellow-red 9/7.5-10 (at anthesis)) throughout, slightly paler inside; spathe tube sometimes green outside, 6.5--7.5 cm long, 1.6--2 cm diam., slightly paler and tinged dull red inside; spadix 8--19 cm long; stipitate 7--10 mm long; pistillate portion green to pale yellow, cylindrical, 7.9 cm long, 1.3--1.4 cm diam. throughout; staminate portion 4--8.4 cm long; fertile staminate portion tapered; pistils glossy, 3.3--3.8 mm long, 2.3--2.6 mm diam.; ovary 5--6-locular, with sub-basal placentation; ovules 1 per locule, style similar to style type C; style funnel shallow, sometimes deep subcylindric; style apex rounded, somewhat flat, with simple funnel; stigma more or less discoid, covering interior faces of stylar funnel. INFRUCTESCENCE (post-anthesis) with seeds 1 per locule, 1.5--1.7 mm long, 7--8 mm diam.