An epiphytic or rarely lithophytic herb. Leaves 4–6, linear-ligulate, unequally roundly bilobed at apex, 22–40 cm long, 2.8–6 cm wide, mid-green. Inflorescence erect-arcuate, 3–7- flowered; peduncle green, mottled purple, shortly pubescent, up to 70 cm long; bracts elliptic, obtuse, 2–4.5 cm long, 2.2 cm wide, yellow, marked with purple, pubescent. Flowers 9–16.5 cm across; pedicel and ovary 4.5–7 cm long, greenish, pubescent, long rostrate. Dorsal sepal elliptic-ovate, obtuse, 3–5.5 cm long, 2.5–3.5 cm wide, undulate and ciliate on margins, pale green, mottled dull purple in basal half, with recurved basal margins. Synsepal elliptic, obtuse, 2.2–4.8 cm long, 2–2.8 cm wide, 2-keeled on outer surface, pale green. Petals often once-twisted in middle, spathulate, subacute to obtuse, 5–9.3 cm long, 1.5–3.1 cm wide, ciliate, pale yellow with a purple apical third and maroon-spotted in basal two-thirds. Lip 3.5–6 cm long, 2.1–3.1 cm wide, dull ochre-brown. Staminode obovate, apically threetoothed with a long erect hook at the base, 10 mm long, 7 mm wide, pale ochre to brownish green. 2n = 26.