Casuarina cunninghamiana, commonly known as river oak, river sheoak or creek oak, is a species of flowering plant in the family Casuarinaceae and is native to Australia and New Guinea. It is a tree with fissured and scaly bark, sometimes drooping branchlets, the leaves reduced to scales in whorls of 6 to 10, the fruit 7–14 mm (0.28–0.55 in) long containing winged seeds (samaras) 3–4 mm (0.12–0.16 in) long.