About the Catchment Area : Flora and Fauna

Drooping Sheoak

The Drooping Sheoak is from the Casuarinaceae family, so named due to the resemblance of the drooping branchlets to the feathers of the Cassowary.

Description and Distribution
Medium sized tree 5-9 metres tall, with a single trunk and continuous rough grey bark. Needle-like branchlets with minute leaves are dark green and pendulously hang from the tree, giving the characteristic 'weeping' appearance. The Drooping Sheoak is a riparian or terrestrial species found in all sub-catchments of the Onkaparinga catchment, mostly in association with grassy Eucalyptus woodland. It is widespread across much of South Australia within a rainfall range of 400 to 900 mm including the Nullarbor, Flinders Ranges and the Southeast. It also naturally occurs in Victoria, New South Wales and Tasmania.

Flowers
The species is dioecious which means that separate male and female flowers occur on separate plants. Therefore trees can be defined as either male or female. Male flowers are small and golden brown, occurring on spikes 4-12cm long. Male trees in full flower will have an overall golden appearance. Female trees produce a cylindrical cone 2-5cm long and 2-3cm in diameter.

Flowering Time: June to August

Hints for Seed Collection
Remember only female plants develop fruit! In the upper catchment, seed can be collected from mid May and June and a little later in the southern parts of the catchment, July to mid August. Wear gloves to collect large, mature cones (fruit), which are grey-brown in colour by twisting them off the branches. Immature cones are tan brown and will hold little or no fertile seed.

Place collected fruit in a warm dry area and within a couple of weeks capsules on the fruit will open up and release seeds.

Mature seed is brown in colour, approximately 5mm long with a flat wing-like attachment making the total length about 1cm.

Hints for Propagation
Sow late winter to early spring. Seed is most viable when stored at least 8 weeks in a cold dry area prior to sowing. Sprinkle seed over a native plant propagation mix or sandy soil mixture and cover with a thin layer of fine gravel. Keep soil moist and store in a warm area. Optimal temperature for germination is 20-25°C.

Habitat and Ecology
Drooping Sheoaks occur on a wide range of soil types including limestone and calcareous sands.

Due to the wide distribution of this plant, use of local provenance seeds is important for success of revegetation projects and preserving heterogeneity within the species. For example, the seed from an upper catchment form cannot be expected to perform well if planted in a coastal area.

They are naturally abundant on sloping landscapes, making them a useful revegetation species for erosion control in steep areas, but are not as successful in flat areas prone to waterlogging.

Allocasuarina verticillata plays an important role in local habitats. The ripening fruit is a natural food source to many parrot species in the Onkaparinga catchment, including the Yellow-Tailed Black Cockatoo. The trees also host many insects and are therefore frequented by small species of insectivorous birds.