Species in this genus are found in tropical and subtropical Asia to Australia and islands of the southwest Pacific Ocean.

Orchids in the genus Pachystoma are deciduous, terrestrial herbs with a branching underground rhizome and one or two linear, papery, pleated or veiny leaves.

[2][3][4] The genus Pachystoma was first formally described in 1825 by Carl Ludwig Blume and the description was published in Bijdragen tot de Flora van Nederlandsch Indie.

[4] As of November 2022, Plants of the World Online lists the following two species of Pachystoma:[1] In 1879, Heinrich Gustav Reichenbach described Pachystoma thomsonianum in The Gardeners' Chronicle,[10] now known as Ancistrochilus thomsonianus (Rchb.f.)

[11] The specific epithet (thomsonianus) honours the Victorian botanist George Thomson.