River sheoak

Casuarina cunninghamiana is a dioecious tree that typically grows to a height of 15–35 m (49–115 ft), has a DBH of 0.5–1.5 m (1 ft 8 in – 4 ft 11 in). Its bark is finely fissured, scaly and greyish brown. The branchlets are often drooping, 100–250 mm (3.9–9.8 in) long, the leaves reduced to scale-like teeth 0.3–0.5 mm (0.01–0.02 in) long, arranged in whorls of 6 to 10 around the branchlets. The sections of branchlet between the leaf whorls (the "articles") are 4–9 mm (0.2–0.4 in) long and 0.4–0.7 mm (0.02–0.03 in) wide. The flowers on male trees are arranged in spikes 4–40 mm (0.2–1.6 in) long, the anthers 0.4–0.7 mm (0.02–0.03 in) long. The female cones are on a peduncle 2–9 mm (0.08–0.4 in) long and sparsely covered with soft hairs. Mature cones are usually 7–14 mm (0.3–0.6 in) long and 4–6 mm (0.16–0.24 in) in diameter, the samaras 3–4 mm (0.12–0.16 in) long.

This casuarina mainly grows in pure stands in open forest on the banks of freshwater rivers and streams in Australia and New Guinea. Subspecies cunninghamiana occurs from Laura, Chillagoe and Augathella in Queensland to Condobolin and Narrandera in New South Wales, and the Australian Capital Territory. Subspecies miodon occurs between the Daly River in the north of the Northern Territory to the Gulf of Carpentaria in Queensland.

River oak is widely recognised as an important tree for stabilising riverbanks and for soil erosion prevention accepting wet and dry soils. The foliage is quite palatable to stock.