[4] Orchids in the genus Phaius are evergreen, terrestrial, sympodial herbs with thin underground rhizomes and crowded above ground, sometimes stem-like pseudobulbs.

The sepals and petals are similar in size and shape and the labellum has three lobes and a shallow pouch near its base.

[2][3][5][6][7] The genus Phaius was first formally described in 1790 by João de Loureiro and the description was published in his book Flora Cochinchinensis.

[8][9] The specific epithet (Phaius) is derived from the Ancient Greek word phaios meaning "dusky" or "brown",[10] referring to the brownish colour of the flowers of many species in this genus.

[5] The following is a list of Phaius species recognised by Plants of the World Online as of September 2023:[11] Orchids in the genus Phaius are found in tropical Africa, India, tropical and subtropical China, Malaysia, the Philippines, Indonesia, New Guinea, New Caledonia, Polynesia and Australia.