Casuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia (north of Northern Territory, north and east Queensland, and north-eastern New South Wales). Populations are also found in Madagascar, but it is doubtful if this within the native range of the species.
The species has been introduced to the Southern United States and West Africa. It is an invasive species in Florida.Casuarina equisetifolia is an evergreen tree growing to 6-35m tall. The foliage consists of slender, much-branched green to grey-green twigs 0.5-1 mm diameter, bearing minute scale-leaves in whorls of 6-8. The flowers are produced in small catkin-like inflorescences; the male flowers in simple spikes 0.7-4 cm long, the female flowers on short peduncles. Unlike most other species of Casuarina (which are dioecious) it is monoecious, with male and female flowers produced on the same tree. The fruit is an oval woody structure 10-24 mm long and 9-13 mm in diameter, superficially resembling a conifer cone made up of numerous carpels each containing a single seed with a small wing 6-8 mm long.
Casuarina equisetifolia is found from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south into Australia (the northern parts of Northern Territory, north and east Queensland, and northeastern New South Wales, where it extends as far south as Laurieton.