Key to the species
1 Ridges narrow, prominently angular, occasionally flat in Casuarina equisetifolia but then densely hairy on ridges as well as in furrows; teeth 6–10, withering or not withering 2
1* Ridges wide, flat or slightly rounded-convex or with a median groove; teeth 8–20, mostly withering 3
2 Branchlets and cones more or less densely and obviously hairy; teeth 6–8, not withering; cone body 10–20 mm long, 10–13 mm diam., with acute bracteoles; samara 6–8 mm long Casuarina equisetifolia
2* Branchlets and cones sparsely and minutely hairy; teeth 8–10, withering; cone body 7–14 mm long, 4–6 mm diam., with broad-acute bracteoles; samara 3–4 mm long Casuarina cunninghamiana
3 Teeth 12–20; ridges smooth, flat or slightly rounded-convex; cones 7–10 mm diam. with thin, broad-acute bracteoles 2.0–2.5 mm wide and with only 1 obvious striation; samara 3.5–5.0 mm long 4
3* Teeth 8–13; ridges minutely roughened, flat or with a median yellowish groove (often masked by wax); cone body 10–16 mm diam. with thick acute bracteoles 3.5–4.0 mm wide and with several obvious striations; samara 5.5–10.5 mm long 5
4 Teeth on young permanent shoots long-recurved Casuarina glauca
4* Teeth on young permanent shoots appressed or slightly spreading Casuarina obesa
5 Teeth erect, appressed, 8–12, 0.5–0.7 mm long; articles 0.6–0.9 mm diam., somewhat waxy, occasionally sparsely hairy; teeth on new shoots erect to somewhat spreading Casuarina cristata
5* Teeth spreading to recurved, 9–13, 0.8–0.9 mm long; articles 1.0–1.8 mm diam., strongly waxy, densely and very shortly hairy; teeth on new shoots spreading Casuarina pauper
