Stems 2--4 m. Branchlets spirally twisted. Leaf blade obovate-oblong, 12--20 × 4--8 cm, glabrescent, base attenuate or subrounded, apex acute. Inflorescences arising from rhizomes, globose or ovoid, ca. 8 cm in diam.; peduncle 4--13 cm; bracts imbricate, oblong, 2.5--4.5 cm, apex sharply pointed; bracteoles 1--1.4 cm, apex sharply pointed. Flowers yellow. Calyx ca. 3 cm, apex slightly widened, 3-toothed; teeth acute at apex. Corolla longer than calyx; lobes linear-lanceolate, subequal, ca. 3.2 cm. Labellum trumpet-shaped, 5--6 cm, base slightly narrowed, margin crisped. Stamen yellowish, petaloid, apex emarginate. Ovary 3-angled. Capsule globose, ca. 1 cm in diam. Seeds black. Fl. Jul--Aug, fr. Sep--Nov. 2 n = 18*.