Trees , 15-35 m, usually not suckering. Bark gray-brown, finely fissured and scaly. Branchlets drooping in vigorous specimens, erect in depauperate specimens; segments 6-9 × 0.4-0.6 mm, sparsely and minutely pubescent in furrows, not waxy, edges of furrows often marked (when dry) by slight ridge; longitudinal ridges angular with median rib; teeth marcescent, [6-]8-10, erect, 0.3-0.5 mm. Young permanent shoots with erect to spreading teeth. Flowers unisexual, staminate and pistillate on different plants. Staminate spikes 0.4-4 cm, 11-13 whorls per cm; anthers 0.4-0.7 mm. Infructescences sparsely pubescent; peduncles 2-9 mm; infructescence body 7-14 × 4-6 mm; bracteoles broadly acute [to acute]. Samaras 3-4 mm.
Flowering summer. Naturally on riverbanks, in somewhat drier sites in the flora; 0-500 m; introduced; Fla.; native, ne, e Australia.
The type subspecies is widely cultivated in many parts of the world. Casuarina cunninghamiana subsp. miodon L. A. S. Johnson is not known to be cultivated.