Stems short or obscure. Leaves 2-7, rather closely spaced, elliptic, oblong to linear-oblong, 7-16 cm long, 1-4 cm wide, apex obtuse or obliquely 2-lobed, base cuneate, articulated. Peduncles and rachis 1015 cm long, 5 mm in diam.; bracts triangular, 2-2.5 mm long, entire or toothed toward apex; pedicel and ovary 5-7 mm long. Flowers numerous, white, often tinged with pale yellow, perianth subspreading, 9 mm in diam.; dorsal sepal obovate, 4.5-5.5 mm long, 2.5-3 mm wide, obtuse; lateral sepals obovate or elliptic, 5-6 mm long, 3-4 mm wide, obtuse at apex, often apiculate; petals obliquely spatulate, 4.5-5 mm long, 1.8-2 mm wide, obtuse; lip mainly a fleshy sac, sac 4-5 mm long, enlarged, 3-lobed at apex, tapering and spur-like at base, lateral lobes erect or ascending, purplish, squarish-orbicular to rectangular, 1-1.5 mm long, obtuse to rounded at apex, midlobe enlarged from saccate spur and protruding toward apex, white, with a purple patch on upper surface at center, composed of solid fleshy tissue, disc slightly depressed at center forming a raised parabolic boundary enclosing depression, depression with 2 raised purple mounds adnate posteriorly to inner wall of lateral lobes and partly blocking mouth of spur; spur pale yellow to pale green, sometimes with purple stripes or spots; column purplish, 1-1.5 mm long, base slightly dilated and continuous into back wall of spur; anther cap white, broadly oval, 1 mm long, 1-locular, with 2 thin membranaceous appendages covering pollinia; pollinia ovoid, 0.8 mm long, undivided or sometimes obscurely sulcate near base, stipe slender, 0.5 mm long; viscidium ovate to clavate, 0.4 mm long; rostellum white. Capsules cylindric, to 4 cm long and 8 mm thick.

TAITUNG: Lanyu Is., Sasaki s. n. May 1924; Su 9239*.

Taiwan, Lanyu Is., in thickets in mountainous regions.

Because of the complicated structure of the lip and column, there still exist some taxonomic and nomenclatural problems in Tuberolabium. According to Wood (1990), T. kotoense is endemic to Taiwan (Lanyu Is.) Closely related species in Tuberolabium and Parapteroceras can be found in the Philippines and Thailand.