Genoplesium brachystachyum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single thin green leaf with a reddish base and 80–120 mm (3–5 in) long, fused to the flowering stem with the free part 10–20 mm (0.4–0.8 in) long.

The description was published in Lindley's book, The Genera and Species of Orchidaceous Plants.

[8] The specific epithet (brachystachyum) in derived from the Ancient Greek words brachys meaning "short"[9]: 708  and stachys meaning "an ear of grain" or "a spike".

[9]: 746 Genoplesium brachystachyum grows in heath and heathy forest, among low shrubs, boulders and rock plates.

It is found in disjunct populations containing fewer than 25 individuals near the north and west coasts.