Acacia pubirhachis Pedley

Shrub or tree, 3-7 m high. Bark splitting into layers, dark reddish brown. Branchlets angular, ±stout, dark brown to black, densely villous-pubescent. Phyllodes narrowly elliptic to linear (sometimes broadest above middle), straight to slightly curved, (3-) 5-12 cm long, 4-8 (-11.5) mm wide, usually acute, sparsely pubescent/silky when young, later subglabrous, with 1 or 2 prominent main nerves continuous to base; minor nerves 4 or 5 per mm, parallel, not anastomosing or running into margins; gland 1, basal, to 1 mm above pulvinus. Spikes 2.5-6 cm long. Flowers 5-merous; calyx 0.5-0.6 mm long, dissected to 1/3, hairy along margins; corolla 1.3-1.6 mm long, dissected to 1/2, glabrous, conspicuously ribbed; ovary densely pubescent. Pods cultrate to oblong, straight-sided, 2-7 cm long, 7-10 mm wide, thinly coriaceous, with very sparse hairs when young, later glabrous; margins prominent, pale. Seeds transverse to slightly oblique, 5-5.5 mm long, brownish black; areole oblong, open.

In Papua New Guinea it is uncommon and grows in heavy clay soils in seasonally waterlogged swamps.Grows in white sand, usually in seasonally waterlogged dune swales or Melaleuca swamps, and occasionally an emergent in heath.