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Allocasuarina sp. in Black Hill, Morialta and Horsnell Gully Conservation Parks

Allocasuarina muelleriana
Black Hill CP March 2004

CASUARINACEAE

Allocasuarina sp.
SheOak or BullOak

The name is made from two parts: allo and casuarina indicating the relationship with the genus casuarina. Casuarina comes from the resemblance of the drooping branches to the feathers of the Cassowary bird. The flowers are unisxual, that is, there are male and female flowers, and indeed, the species in our parks, generally have the male and female flowers occuring on separate plants. The leaves are reduced to scales along the segmented branchlets.

These plants are very distinctively Australian plants, that are a much loved part of the landscape. The common names of SheOak and BullOak speak of the qualities of the timber of these shrubs and trees.

Allocasuarina muelleriana. provide
the colour. May 2005, Black Hill CP

• Allocasuarina muelleriana ssp muelleriana
• Allocasuarina verticillata

Allocasuarina muelleriana ssp muelleriana: common oakbush or slaty she-oak.

This species is named after Baron Ferdinand von Mueller, a German born botanist, physician and geographer (30 June 1825 to 10 October 1896).

These shrubs can grow to 4m tall, but most of the time are much smaller, perhaps a metre and a half, depending on the growing conditions.

The male flowers occur along one to five centimetres at the ends of the branchlets. The leaves are like teeth around the stems, and they divide the stems into segments. The female flowers are also red, and quite small on the branches.

This species takes on russett tones in the summer months that give the dark colour that has given Black Hill its name.

Fire Response
There are two ways Allocasuarina muelleriana ssp muelleriana has of dealing with fire:
Firstly, the plants are able to regrow from the base if not damaged too badly (young plants are not likely to survive). Once burnt, plants quickly reach maturity, and start setting seed.
Secondly, new plants will grow from seed. Populations are likely to survive a fire event through these mechanisms, but are unlikely to colonise a new area burnt by fire.

Allocasuarina muelleriana. male flowers July 2002, Black Hill CP

Allocasuarina muelleriana. female flowers Aug 2007, Black Hill CP

Allocasuarina muelleriana. male flowers Aug 2007, Black Hill CP

Allocasuarina striata 9 August 2009,
Horsnell Gully CP

Allocasuarina striata: stalked oakbush.

This plant can be found in the project area near the entrance to the Park. It is an an attractive large shrub to 4m tall. The cones are held on short stalks between 3 and 12mm.

The female plants in Horsnell Gully have bright red flowers.

The name striata means striped or fluted.

Allocasuarina striata. Male flowers August 2009, Horsnell Gully CP

Allocasuarina striata, female flowers, August 2009, Horsnell Gully CP

Allocasuarina striata. Last years cones August 2009, Horsnell Gully CP

Allocasuarina verticillata: drooping sheoak.

Allocasuarina verticillata Cones on this female plant can be seen June 2008, Morialta cp

June 2008 Male flowers can be seen here Morialta Conservation Park.

This species was previously named Allocasuarina stricta and Casuarina stricta.

A small tree, growing to 9 metres tall. This is one of the iconic species of our parks and well known for the sound of the wind blowing through it's branchlets. If you are visiting Morialta Main valley on a windy day, be sure to spend some quite time listening to this sound, as the wind blows through the trees at the tops of the valley. It is an important food source of the Glossy Black Cockatoo, which now has a range reduced to Kangaroo Island.

Allocasuarina verticillata. Female flowers June 2009, Black Hill CP	Allocasuarina verticillata. Seed cones, June 2009, Morialta CP
Allocasuarina verticillata. Male flowers June 2009, Black Hill CP	Allocasuarina verticillata. Male flowers

Fire Response
Allocasuarina verticillata survives fire vegetatively, and through the germination of seeds. Plants which regrow vegetatively take nearly as long to reach maturity as a plant germinating from seed. There is reasonable confidence that a population will survive a fire event, but they are unlikely to colonise a new area burnt by fire.

Allocasuarina verticillata. February 2004, Black Hill CP

Allocasuarina verticillata. June 2008, Morialta CP

Allocasuarina verticillata. June 2008, Morialta CP

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Extra photos and text added 9 August 2009
Sources: e-Flora of SA, Wikipedia, Encyclopeadia of Australian Plants.