Tufted terrestrial herbs. Roots 5-6 mm thick. Pseudobulbs small, clavate, 1-2 cm tall, enclosed by leaf sheaths and membranaceous scales. Leaves 4-5 on each pseudobulbs, linear, 60-80 cm long, 7-12 mm wide, light green, membranaceous, apex acute, recurved and slightly conduplicate toward base, canaliform at base, with 3 main veins elevated on lower surface, minutely serrulate on margins. Peduncle erect, slender, 10-20 cm long, with solitary or rarely 2 flowers, enclosed by several bract-like sheaths toward base, sheaths lanceolate, to 6 cm long; floral bracts linear-lanceolate, 4-5 cm long; pedicel and ovary 4 cm long. Flowers fragrant, variable in color, usually pale green to yellowish white, with reddish veins, 5-8 cm in diam.; sepals linear-oblong, 3.6-4.8 cm long, 8-10 mm wide, apex acute, slightly contracted at base, lateral ones slightly oblique; petals oblong or ovate-lanceolate, 2.6-3.2 cm long, 1 cm wide, acute, with conspicuous red band along midrib; lip 3-lobed, oblong, 2-2.5 cm long, 1 cm wide, lateral lobes erect, rounded, with large red patches, midlobe strongly reflexed, whitish and dotted with red, disc with 2 fleshy yellow keels; column slightly curved, 1.4-1.6 cm long, yellowish, with dense reddish patches on ventral side; anther erect, nearly bell-shaped, yellowish white, 2-celled; pollinia 4, in 2 unequal pairs. Capsules ellipsoid, 5-6 cm long, 2 cm in diam., pedicels 2-3 cm long.

TAIPEI: Wulai, Su s. n. Apr 1973. TAICHUNG: Lishan, Su 593. NANTOU: Chtou Su 533*; Hoshe, Su 7693.

China, Korea and Japan. Taiwan, forests at 900-1,800 m throughout, usually found on east or southeast slopes just below mountain ridges.