Allocasuarina

From Wikipedia, the free encyclopedia

iAllocasuarina

Allocasuarina verticillata foliage and fruit

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Fagales
Family:	Casuarinaceae
Genus:	Allocasuarina L.A.S.Johnson

Species

61 species; see text.

Image:Allocasuarina littoralis.jpg

Allocasuarina is a genus in the flowering plant family Casuarinaceae. They are endemic to Australia, occurring primarily in the south. Like the closely related genus Casuarina, they are commonly called sheoaks or she-oaks, they are notable for their long, segmented branchlets that function as leaves. Formally termed cladodes, these branchlets somewhat resemble pine needles, although sheoaks are actually flowering plants. The leaves are reduced to minute scales encircling each joint. Fallen cladodes form a dense, soft mat beneath sheoaks, preventing the development of undergrowth and making sheoak woods remarkably quiet.

Another characteristic feature are the spiny "cones", about the size of an acorn but with a texture more resembling a conifer cone. However, sheoak "cones" are actually a woody fruit.

As with legumes, sheoak roots possess nodules containing symbiotic nitrogen fixing bacteria; together with their highly drought adapted foliage, this enables sheoaks to thrive in very poor soil and semi-arid areas. However, sheoaks are much less bushfire tolerant than eucalypts.

Fossils of closely related species have been found dating back to the time of Gondwana.

[edit] Uses

The hard wood and rich texture makes sheoak wood popular among wood-turners. Sheoak wood is also regarded as an excellent firewood as it burns with very little ash.

Because of its ability to grow and develop extensive root systems in very poor or sandy soils, and to completely cover the ground with its "needles", it is often used to stabilise soils in erosion prone areas, or on sand dunes. Sheoak is also used as an ornamental shrub, although for this purpose the mat of "needles" may become a nuisance and must be carefully considered.