Casuarina is a genus of 17 species in the family Casuarinaceae,
native to Australasia, southeast Asia, and islands of the western
Pacific Ocean. It was once treated as the sole genus in the family,
but has been split into three genera (see Casuarinaceae).
Fruit of C. equisetifolia
They are evergreen shrubs and trees growing to 35 m tall. The
foliage consists of slender, much-branched green to grey-green twigs
bearing minute scale-leaves in whorls of 5–20. The flowers are
produced in small catkin-like inflorescences; the flowers are simple
spikes,. Most species are dioecious, but a few are monoecious. The
fruit is a woody, oval structure superficially resembling a conifer
cone made up of numerous carpels each containing a single seed with
a small wing. The generic name is derived from the Malay word for
the cassowary, kasuari, alluding to the similarities between the
bird's feathers and the plant's foliage, though the tree is
presently called "Rhu" in current standard Malay.
Casuarina species are a food source of the larvae of hepialid
moths; members of the genus Aenetus, including A. lewinii and A.
splendens, burrow horizontally into the trunk then vertically down.
Endoclita malabaricus also feeds on Casuarina. The noctuid Turnip
Moth is also recorded feeding on Casuarina.
Casuarictin, a type of tannin, is found in the species within the