Pseudobulbs erect or prostrate, conic-ovoid, 1-4 cm tall, 0.8-2 cm in diam., dark purplish or greenish. Leaves developed after anthesis, oblanceolate or elongate-oblong, 15-40 cm long, 3-7 cm wide, apex acute, base cuneate, nearly sessile, plicate, mainly 5-nerved. Peduncle arising with young leaves from base of old pseudobulb, ca. 6-10 cm tall, with solitary flower or rarely with few flowers in raceme; bracts leaf-like, lanceolate, 2.5-4 cm long; pedicel and ovary 2.2-3 cm long, usually curved downward. Flowers purple or rarely white, large and showy; sepals subequal, spatulate or oblanceolate, 4-5.5 cm long, 0.9-1.2 cm wide, apex acute, contracted at base, 7-nerved; petals similar to sepals but slightly longer and narrower; lip trumpet-shaped, convolute and surrounding column at base, emarginate and fimbriate at spreading apex, obovate-rhombic when expanded, 4-5 cm long, 3-4.3 cm wide, disc yellowish and with dark spots in front, whitish and with dark stripes backward, with 3-5 longitudinal keels, keels ranging from 2 to 4 cm long, undulate or serrate, continuous or interrupted midway; column whitish, 3-4 cm long, 4 mm wide, enlarged and slightly winged at apex, narrowed toward base; anther ovoid, 3.5 mm long; pollinia 4, 2 superposed pairs, cylindric-clavate, connected at narrow base; stigma under rostellum, slightly convex; rostellum nearly orbicular, ca. 3.5 mm in diam. Capsules fusiform to cylindrical, 3-4 cm long, with stalk ca. 1.5 cm long, peduncle considerably elongate when mature. Seed fusiform, 0.5-1 mm long.

TAIPEI: Taitonshan, Sasaki 40035; North Chiatienshan, Su 1026. ILAN: Chilanshan, Ou 602; Yuanyung Lake, Su & Chen 8118. TAOYUEN: Lalashan, Su 8193. TAICHUNG :Shiyuan, Su & Chen 7175; Anmashan, Huang 8098; Menyueh, Su & Chen 7854*. KAOHSIUNG: Hinokiyama, Tanaka 1542. HUALIEN:Tailukuo, Liu et al. s. n. Aug 1956; Lintienshan, Su 8201.

Widespread in China (central and southern parts, including Tibet). Taiwan, cloud forests, 12002500 m , usually with mosses on rocks and tree trunks.

The plants in Taiwan vary greatly in size, flower color and size, and in number and form of the keels on the lip.