It has smooth, powdery white bark, lance-shaped to curved adult leaves, flower buds in groups of seven, white flowers and cup-shaped, hemispherical or conical fruit.Eucalyptus mannifera is a tree that typically grows to a height of 20–25 m (66–82 ft) and forms a lignotuber.

It has smooth, powdery, white or grey bark, sometimes with red patches, and which is shed in short ribbons, flakes or plates.

The flower buds are arranged in leaf axils in groups of seven on an unbranched peduncle 5–10 mm (0.20–0.39 in) long, the individual buds on pedicels 1–5 mm (0.039–0.197 in) long.

[2][3][4][5] Eucalyptus mannifera was first formally described in 1834 by Robert Mudie from a specimen collected in the Blue Mountains, and the description was published in the Transactions of the Royal Medico-Botanical Society of London.

Three subspecies names have been accepted by the Australian Plant Census: Brittle gum is widespread in south-eastern New South Wales, south from Rylstone and in eastern Victoria.