Casuarina is a genus of 17 species in the family Casuarinaceae, native to Australia, the Indian Subcontinent, 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).
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 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.
C. cunninghamiana, C. glauca and C. equisetifolia have become naturalized in several countries, including Argentina, Cuba, China, Egypt,Israel, Iraq, Mauritius, Kenya, Mexico, South Africa, Rio de Janeiro, the Bahamas and the southern United States; in the United States it was introduced in the early 1900s, and is now considered an invasive species. The species has nearly quadrupled in southern Florida between 1993 and 2005, where it is known as Australian pine.
C. equisetifolia is widespread in the Hawaiian Islands where it grows both on the seashore in dry, salty, calcareous soils and up in the mountains in high rainfall areas on volcanic soils. It is also an introduced, invasive plant in Bermuda, where it was introduced to replace the Juniperus bermudiana windbreaks killed by juniper blight in the 1940s. Now the ironwoods are growing on cliffs and sandy slopes strangling all surrounding plants, or covering them in needles; they also erode the cliffs by digging their roots deep into them and splitting them apart.
Casuarina and Allocasuarina spp are strongly suspected of having allelopathic properties, as evidenced by the total or near absence of understory once a mat of litter develops around the plants.
From Wikipedia, the free encyclopedia
Photos Zakaki 8/11/2014 by George Konstantinou
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