Thunb. in J.A.Murray, Syst. Veg. ed. 14 : 817 (1784)
A terrestrial herb 25-45 cm tall, with a slender flexuous creeping rhizome, 15-40 cm long, 0.2-0.3 cm in diameter, bearing occasional scales and bunches of roots at intervals. Stems erect, slender, 0.4-0.5 cm in diameter, densely tomentose hairy, enclosed in several obtuse overlapping sheaths in lower part, bearing two subopposite leaves just above the middle. Leaves more or less horizontal, flabellate from a short sheathing base, rounded, obtuse or apiculate at the apex, 8-16 cm long, 7-23.5 cm wide, the margins undulate all round, usually glabrous but sometimes sparsely hairy, with radiating veins which apparently terminate at the margin. Inflorescence one-flowered, erect; peduncle slender, terete, 7-12 cm long, hairy; bract leafy, ovate or lanceolate, acute or acuminate, 3-6.5 cm long, 0.4-5.2 cm wide. Flower nutant, the sepals and petals pale yellow or yellow-green with purple spots at the base, the lip whitish or yellowish pink with carmine or crimson spots and veins, more intense on the inner surface, the staminode purplered with a green or yellow central line; pedicel and ovary 1.4-3 cm long, densely pubescent. Dorsal sepalincurved, lanceolate, acuminate, 4-6 cm long, 1.5-2.5 cm wide; synsepal elliptic-ovate, acuminate and bidentate at apex, 3.5-5 cm long, 1.2-2 cm wide. Petals falcate, lanceolate, acuminate, 3.5-6 cm long, 0.8-1.2 cm wide, hairy at the base on inner side. Lip calceiform, pendent, somewhat Lshaped in side view, with a crimped and grooved apical part, 3.8-6 cm long, 3-3.5 cm across. Column greenish-white, about 1 cm long; staminode convex, ovate or cordate, with two obscure longitudinal ridges, 1 cm long, 0.8-0.9 cm wide.