Acacia pachyphylla is a shrub belonging to the genus Acacia and the subgenus Phyllodineae that is endemic to south western Australia.
The low, spreading and pungent shrub typically grows to a height of 0.1to. It has multiple glabrous stems with light grey coloured branchlets that are a reddish colour toward the extremities and has persistent stipules that are in length. Like most species of Acacia it has phyllodes rather than true leaves. The grey-green phyllodes are dimorphic on the upper branches and are in width. On the lower branches the thickly coriaceous phyllodes are caducous with an oblanceolate shape and have a length of and are wide.[1] It blooms from October to December and produces yellow flowers. The rudimentary inflorescences occur singly on a raceme with a long axis with spherical flower-heads that have a diameter of and contain 36 to 53 golden coloured flowers. The seed pods that form after flowering are not constricted between each of the seeds. The hard and bony pods are up to in length and wide and are covered in a fine white powdery coating. The dull dark brown to black coloured seeds inside the pods have an oblong to broadly elliptic shape with a length of and a terminal cap shaped aril.[1]
It is native to an area along the south coast in the Goldfields-Esperance region of Western Australia where it is commonly situated on flat or undulating sandplains or along the margins of salt lakes growing in sandy soils over or around limestone or sandy-loamy, clay or gravelly soils The bulk of the population is found from around Young River in the west to around Israelite Bay in the east and extending as far north as where it is often a part of open shrub mallee over heathland communities.[1]