Prasophyllum bagoense is a terrestrial, perennial, deciduous, herb with an underground tuber and a single tube-shaped leaf, 200–450 mm (7.9–17.7 in) long and 3–4 mm (0.12–0.16 in) wide.

[2][3][4][5] Prasophyllum pallens was first formally described in 2000 by David Jones from a specimen collected on Mount Banks and the description was published in The Orchadian.

[7] Slaty leek orchid grows in dense, low heath in shallow sandy soil over sandstone at altitudes of 1,000–1,100 m (3,300–3,600 ft) in the higher parts of the Blue Mountains of New South Wales.

Prasophyllum pallens is listed as "vulnerable" under the New South Wales Government Biodiversity Conservation Act 2016.

It was one of eleven species selected for the Save a Species Walk campaign in April 2016; scientists walked 300 km to raise money for collection of seeds to be prepared and stored at the Australian PlantBank at the Australian Botanic Garden, Mount Annan.