Belonging to the Casuarinaceae family, these plants are instantly recognised by their needle-like foliage and the wonderful sighing sound of the wind passing through them. Around Narrogin we tend to notice the trees most: Rock Sheoak; Allocasuarina huegeliana on well drained soils, and Salt Sheoak; Casuarina obesa in semi saline lakes and waterways. A bed of sheoak needles with a whispering wind overhead is a wonderful place for courting couples (after they have repelled the ants, ticks and mosquitos).
The common name Sheoak was first given to Rock Sheoak by early European settlers who thought the wood resembeld that of the European oak but was inferior, and being sexists called it she-oak.
The genus name Casuarina is derived from the Malay word for cassowary, due to similarities of layered feathers/ needles. If you look closely at a needle you will notice rings of scales, which are the true leaves. The green needles are in fact photosynthesising stems. Casuarinas and Allocasuarinas have subtle differences in cone structure and needle orientation. Allocasuarina means opposite to Casuarina, referring to needle orientation.
Tammas or tammars, are shrubs, which become dominant on gravelly soils generally east of a line through Yealering and Harrismith.
Casuarinaceae have male and female plants (dioecious), but differ from the animal world in that the females have the nuts (cones).
Male plants produce pollen that is blown by wind to female flowers. Like most wind pollinated species, huge amounts of pollen are produced, and you will notice now green female and orange pollen-bearing males everywhere.
The common name Sheoak was first given to Rock Sheoak by early European settlers who thought the wood resembeld that of the European oak but was inferior, and being sexists called it she-oak.
The genus name Casuarina is derived from the Malay word for cassowary, due to similarities of layered feathers/ needles. If you look closely at a needle you will notice rings of scales, which are the true leaves. The green needles are in fact photosynthesising stems. Casuarinas and Allocasuarinas have subtle differences in cone structure and needle orientation. Allocasuarina means opposite to Casuarina, referring to needle orientation.
Tammas or tammars, are shrubs, which become dominant on gravelly soils generally east of a line through Yealering and Harrismith.
Casuarinaceae have male and female plants (dioecious), but differ from the animal world in that the females have the nuts (cones).
Male plants produce pollen that is blown by wind to female flowers. Like most wind pollinated species, huge amounts of pollen are produced, and you will notice now green female and orange pollen-bearing males everywhere.
In our bush the vast majority of plants in the bush have root modifications (cluster or proteoid roots) and alliances with fungi (mycorrhizas), which enhance their ability to access nutrients and water and to build a 'niche' to give them an advantage over others.
Plants on poor sand or gravel soils often have cluster roots that are also instrumental in forming gravels.
Eucalypts and other plants on more fertile soils mainly use mycorrhizas.
Casuarinaceae are very adaptable. They have cluster roots, ectomycorrhizas (where the fungus does not invade the plant root), AND nodules where bacteria produce nitrogen like legumes.
Allocasuarina huegeliana was named Rock Sheoak because it mostly occurred around granite rock outcrops. Competition by other plants and grazing of seedlings by by native marsupials restricted their spread. Small marsupial extinction has allowed the sheoaks to spread, and thick needle cover suppresses other plants. Since European settlement they have spread greatly on roadsides and other well drained areas of bush. I frequently see roads with remnant wandoo vegetation on one side of a road and rock sheoak thicket on the disturbed other side.
Plants on poor sand or gravel soils often have cluster roots that are also instrumental in forming gravels.
Eucalypts and other plants on more fertile soils mainly use mycorrhizas.
Casuarinaceae are very adaptable. They have cluster roots, ectomycorrhizas (where the fungus does not invade the plant root), AND nodules where bacteria produce nitrogen like legumes.
Allocasuarina huegeliana was named Rock Sheoak because it mostly occurred around granite rock outcrops. Competition by other plants and grazing of seedlings by by native marsupials restricted their spread. Small marsupial extinction has allowed the sheoaks to spread, and thick needle cover suppresses other plants. Since European settlement they have spread greatly on roadsides and other well drained areas of bush. I frequently see roads with remnant wandoo vegetation on one side of a road and rock sheoak thicket on the disturbed other side.
 Rock Sheoak female flower and cone |  Male Rock Sheoak loaded with pollen |  Mixed male and female trees |
| narrogin_sheoaks_tammas.pdf |
 Female (left) and male dwarf sheoak |  Wheatbelt Tammar Allocasuarina campestris |
There are lots of tammas (all Allocasuarinas), particularly on kwongan soils, which are often overlooked because they don’t have conventional flowers. Foxes Lair has Dwarf Sheoak; Allocasuarina humilis on gravels, and Allocasuarina microstachyia that only occurs on the south side of the Claypit.
My favourite is the compass bush; Allocasuarina pinaster, which occurs in the Lake Grace area on grey sandy gravels. The nearest Location is Holden Road near Tarin Rock.
My favourite is the compass bush; Allocasuarina pinaster, which occurs in the Lake Grace area on grey sandy gravels. The nearest Location is Holden Road near Tarin Rock.
 Compass bush plant |  Compass bush fruit |