Allocasuarina

Allocasuarina species

Synonyms - Casuarina species

Family: Casuarinaceae

Names:

Sheoak

Other Names:

Summary:

Shrubs or small trees with needle like "leaves". The real leaves are tiny teeth encircling the branchlets like paper crowns.

Description:

Cotyledons:

First leaves:

Leaves:

The "leaves" are green, wiry branchlets with 4-10 ribs and jointed. Branchlets are often pendulous or weeping.
The real leaves are scales in rings of 4-10 around the branchlets.
Stipules - None.
Petiole - None.
Blade - Tiny scale.

Stems:

Flower head:

Male spike simple, red-brown, with many rings of bracts, on a branchlet that is different to vegetative branchlets. 1 flower per axil.
Female cone is egg shaped, at the end of a branchlet amongst or below vegetative branchlets. The exposed portion of the bracts are thin. The valves are thickened and often have 1 or more outgrowths.

Flowers:

Small, stalkless
Wind pollinated.
Ovary - 1 celled at maturity with 2 ovules or rarely 4.
Style - Usually reddish with 12 long thread like branches, each with a long stigma.
Stamens - 1
Anthers - 2 celled.

Fruit:

Shiny brown to black nut with wings or long hairs.

Seeds:

Winged.

Roots:

Key Characters:

Trees with jointed branchlets.
Leaves reduced to minute whorled teeth at the nodes.
Scales leaves in rings of 4-10 around the branchlets. Valves thick, not ribbed, the adaxial surface often with tubercles or appendages.
Flowers unisexual.
Seeds winged and developed in small woody cones.
From B. L. Rye and Nancy Burbidge.

Biology:

Life cycle:

Perennial.

Physiology:

Reproduction:

By seed.

Flowering times:

Depends on species but usually winter, spring or summer.

Seed Biology and Germination:

Vegetative Propagules:

None

Hybrids:

None

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed.

Origin and History:

Australia.

Distribution:

ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Various species widely spread across Australia.

Habitats:

Climate:

Temperate Mediterranean.

Soil:

Generally prefers sandy soils.

Plant Associations:

Significance:

Beneficial:

Ornamental

Detrimental:

Toxicity:

Not recorded as toxic.

Legislation:

The Wildlife Conservation Act prohibits removal of native plants from the wild in their native range on government land.

Management and Control:

Normal clearing and grazing controls it.

Thresholds:

Eradication strategies:

Herbicide resistance:

None recorded.

Biological Control:

Unlikely because many are Australian native plants.

Related plants:

Dwarf Sheoak (Allocasuarina humilis)
Horned Sheoak (Allocasuarina thuyoides)
Allocasuarina fraseriana
Allocasuarina huegeliana
Allocasuarina lehmanniana
Allocasuarina microstachya

Plants of similar appearance:

Swamp Sheoak (Casuarina obesa)
Casuarina cunninghamiana is an eastern states species that has escaped along a creek In John Forrest National Park near Perth.
Casuarina equisetifolia is an eastern states species growing at the mouth of the Greenough River near Geraldton in WA.
Casuarina glauca is an eastern states species that has escaped at Pelican Point in Perth.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne).

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia).

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Marchant et al (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P73.

McBarron, E.J. (1983). Poisonous plants. (Inkata Press, Melbourne).

Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne).

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.