IUCN Red List of Threatened Species https://www.iucnredlist.org/species/191704/1999308
Thailand, Cambodia and Laos; 300–1300 m altitude.
A terrestrial herb. Leaves 3–5, narrowly elliptic, oblong-elliptic or obovate, tridenticulate at acute apex, 10–20 cm long, 3.2–4.8 cm wide, ciliate at base, tessellated pale and dark above, sometimes purple at base on lower surface. Inflorescence 1- (or rarely 2-) flowered, 20–40 cm tall; peduncle purple, purple-pubescent, 12–25 cm long; bract ovate to elliptic, acute to subacute, 1.5–2.8 cm long, 1.5–2 cm wide, green, sometimes marked with purple, ciliate. Flower large, 8–11 cm across; sepals white flushed with purple in lower half, veined with purple and green; petals white to yellow-green with a purple apical third, spotted with maroon on upper margin and sometimes in basal half; lip green, heavily flushed deep maroon; staminode pale green with darker veins, flushed purple; pedicel and ovary 3–6.5 cm long, green, flushed with purple, purple-pubescent. Dorsal sepal broadly ovate to subcircular, apiculate, 4–5.5 cm long, 4.2–6 cm wide, with recurved ciliate margins. Synsepal concave, elliptic or lanceolate, acute, 2.7–3.2 cm long, 1.6–2.5 cm wide. Petals sometimes reflexed, subsigmoid, ligulate, obtuse or rounded at apex, 4.6–6.8 cm long, 1.2–1.8 cm wide, maroon-ciliate. Lip 2.5–4.4 cm long, 2–2.5 cm wide, warty on incurved side-lobes. Staminode lunate, 11 mm long, 7 mm wide, apical lateral teeth falcate, acute to obtuse.
Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592
