It is a dioecious small tree or shrub that forms root suckers, and has drooping or spreading branchlets, the leaves reduced to scales in whorls of 12 to 16, the fruit 10–20 mm (0.39–0.79 in) long containing winged seeds (samaras) 3–5 mm (0.12–0.20 in) long.

Casuarina obesa is a dioecious shrub or small tree that typically grows to a height of 3–15 m (9.8–49.2 ft) and has corky, deeply fissured bark.

[2][4][5][6][7] This species is the western and inland variant of C. glauca, but differs in having erect teeth on new shoots.

[10] Swamp she-oak grows in moist, often brackish or saline places along watercourses and near salt lakes.

The main threats to the species include grazing by livestock and rabbits, weed invasion and land clearing.