Often confused with Phaius wallichii.
The former species (ie tankervilleae) originally described from Chinese material, has sub-nutant (semi nodding) flowers with sepals and petals that are tan brown within and white outside, a trumpet shaped lip with a broad purple margin and blunt apex and a short spur (less than 9mm long).

The other (ie walichii) has larger flowers with more spreading, ochre coloured sepals and petals and a conical, acute lip (ie pointed apex) which is predominantly white with a yellow & purple band in the throat, and a spur up to 20mm long. The latter has been referred to in Hong Kong as the ''Kadoorie'' Phaius (it was first found growing on the estate of the Kadoorie Botanical Garden in the new Territories) and clearly does not fall within the variation of P. tankervilleae as usually understood. A similar plant was illustrated in colour by Chen et al (1994). However, in its floral morphology it matches closely the species described from the Himalayas as P. wallichii and from Sri Lanka as P. bicolour.

Phaius tankervilleae and Phaius walichii, a pair of confused species
by Phillip Cribb, Mei Sun and Gloria Barretto
Kew Bulletin Vol. 59, No. 4 (2004), pp. 547-554 (8 pages)