Terrestrial, with basal fleshy pseudobulbs and leafy stems, to 100 cm tall. Pseudobulbs elongate clavate or nearly columnar, 20-35 cm long, slightly tapering upward, 1.5-4 cm thick at base, with 3-5 internodes, covered by membranaceous sheaths when young, green and glabrous. Stem from apex of pseudobulb, 30-70 cm long, ca. 1 cm in diam., totally enclosed by leaf sheaths. Leaves 5-8, more or less distichous, oblong to lanceolate, increasing in size upward, 15-40 cm long, 5-8 cm wide, apex acuminate, base cuneate, decurrent and continuous to sheath. Racemes arising from lower nodes of pseudobulbs, peduncle erect, 30-50 cm long, 4-8 mm in diam., glabrous, with 3-4 sheaths from middle downward; bracts persistent, ovate-lanceolate, 6-10 mm long, acute at apex; pedicel and ovary 2-2.5 cm long, sparsely pubescent or nearly glabrous. Flowers 4-10, pale yellow to lemon yellow, ca. 4-5 cm across; sepals subequal, oblong to oblanceolate, 3-3.5 cm long, 7-10 mm wide, obtuse to subacute at apex, lateral sepals slightly oblique, decurved; petals oblanceolate, ca. 3 cm long, 6-8 mm wide, apex acute, base narrowed; lip whitish, often tinged with yellow, involute, forming an open tube below column or partly enclosing column, nearly orbicular when expanded, ca. 2.5 cm long, continuous into a short spur at base, apex more or less 3-lobed, lateral lobes shallowly truncate or ovate, +/- undulate, central lobe orbicular-square, emarginate, plicate-undulate; disc with 2 or 3 low yellow ridges, spur greenish yellow, obconic, opening broad, abruptly narrowed into a slender tube ca. 5-6 mm long, tip often curved toward ovary; column whitish, stout, 20-25 mm long, 6 mm wide, connate with base of lip (spur tube) for nearly 1/3 its length, apex dilated, winged laterally, middle slightly constricted, base enlarged, connate with spur, densely white-hirsute on ventral surface; anther white or tinged with brownish yellow, ovate, 3 mm long; pollinia 8, connected in two groups by small viscidium, 1.5-2 mm long; stigma semiorbicular; rostellum ligulate, 2.5 mm long, bent downward, obtuse at apex. Fruit fusiform-ellipsoid, to 6 cm long. Seeds linear-fusiform, ca. 1 mm long.

NANTOU: Neimaopu, Su et al. 7688, 8065*.

China (Yunnan). Taiwan, moist, broadleaved forests at ca. 500 m , uncommon.

This species is quite similar to Phaius columnaris C. Z. Tang & S. J. Chen, which was recently discovered in Kwangtung, China. In P. columnaris, the columnar pseudobulbs are longitudinally ridged, the flowers are larger, with wider sepals and petals, and the lip is tinged orange red. That species grows on xeric rocky sites rather than in moist forests.