bernaysii is an evergreen, terrestrial herb with fleshy, crowded pseudobulbs 50–70 mm (2–3 in) long and wide.

There are between four and eight pleated, lance-shaped, dark green leaves 50–125 cm (20–50 in) long and 80–100 mm (3–4 in) wide, with the narrower end towards the base.

[2][3][4] The yellow swamp orchid was first formally described in 1873 by Heinrich Gustav Reichenbach and given the name Phaius bernaysii, giving credit to "Dr Rowland" for the discovery.

A later edition of The Gardeners' Chronicle included a letter from Lewis Bernays explaining that he himself had collected the specimens and sent them to Ferdinand von Mueller and to his friend "Dr Rowland of Malvern" for him to take to "the eminent firm of Messrs. Veitch & Son", (possibly Veitch Nurseries in London).

The main threats to the species are illegal collection of the plants and flowers, inappropriate fire regimes and changes in swamp hydrology due to human activities.