No. 7 Allocasuarina IN THIS ISSUE DAllocasuarina This issue of Seed Notes The name Casuarina comes will cover the genus from the neo-Latin casuarius Allocasuarina. meaning cassowary, due to the resemblance of the D Description drooping branchlets to the D Geographic feathers of the Cassowary distribution and bird. The Greek allos, habitat meaning other, has been D Reproductive biology added to the word to refer to the relationship with the D Seed collection genus Casuarina. The common D Seed quality name of ‘she oak’ was given assessment to the genus in reference to D Seed germination the timber, which is oak-like in appearance. D Recommended reading D Jointed leaves of Allocasuarina ramosissima. Photo – Anne Cochrane Description Allocasuarina species (family purposes, for fuelwood or DCasuarinaceae) may be forestry and joinery timber. dioecious or monoecious They have an important role trees or shrubs with soft in stabilising coastal dunes wispy pendulous branchlets. and riverbanks. Some species The leaves of Allocasuarina are reasonably salt-tolerant are seemingly absent and are and have been used in the reduced to ‘teeth‘ that whorl amelioration of saline soils. around the small branchlets Others are effective as wind that are jointed at regular breaks or shelter belts. The intervals. The male flower foliage of some species is is an elongated spike; the palatable to stock in times of female flower is globular or drought. Above: Allocasuarina fibrosa. ovoid and reddish in colour. Below: Allocasuarina humilis. A variety of species have D Photos – Anne Cochrane been used for ornamental Allocasuarina tessellata. Photo – Sue Patrick
Seed Notes 7 page 1 Geographic distribution and habitat Seed collection Allocasuarina is a genus The fruiting body of Allocasuarina Dendemic to Australia, whereas is a woody cone and the fruit itself Casuarina is more widespread. is a winged nut or samara (dry Allocasuarina consists of about indehiscent winged fruit). The seed 50 species and subspecies that is solitary within each samara and are found mainly in southern embryonic, meaning there is no food Australia. Less than half of body around the embryo. The cones these are endemic to Western themselves contain many seeds, and Australia. Plants usually grow are generally mature within a year of in impoverished soils but can flowering. Flowering can occur from be found in the arid inland, in Approximate distribution of autumn to spring and many species Allocasuarina in Australia. swamps, on riverbanks and by retain their cones for several years, the coast. They have a preference being termed serotinous or canopy for well-drained soils, both light and heavy, stored. Cone collection is easy. Maturity although some species may withstand waterlogging. is generally indicated by a change D in cone colour from green to pale brown to dark brown. Cones from the Reproductive biology previous year can be collected, making D sure that the valves of the cones are Allocasuarina are wind not open. Cones with open valves are pollinated and their seeds are likely to be devoid of seed because wind dispersed. Because of it would already have been released. wind pollination, plants are Secateurs should be used when Above: Allocasuarina tessellata. generally outcrossing, and taking cones from the fruiting Photo – Sue Patrick very little hybridisation occurs branches. In some cases pole within the genus. The roots pruners will be required for the of the Allocasuarina have collection of cones due to the height nodules that fix atmospheric of trees. nitrogen and therefore aid in soil nutrition. Parrots often predate the developing fruits. Cones of Allocasuarina are D often found in emu scats and it appears that the old cones Right: Allocasuarina seed. help in the digestion of food Below: Immature cones of Allocasuarina ramosissima. eaten by these birds. It is Above: Allocasuarina tessellata. Photos – Anne Cochrane not thought that this aids Photo – Sue Patrick germination of the seed. Some species are root suckering and will resprout when damaged. D
Left: Allocasuarina ramosissima. Photo – Anne Cochrane
Seed Notes 7 page Seed quality assessment Cones open readily at maturity if placed in a dry warm position. DMany Allocasuarina produce seed that appear intact but are actually empty. A simple cut-test of a representative portion of the seed (sectioning the seed to see what percentage of the total is filled) will tell you how many seed in your collection are good. If the endosperm is absent or shrivelled, discard these seed. D
Above: Winged Allocasuarina fibrosa seeds. Left: Note the difference between the state of the contents of the samara. On the left a firm white endosperm; on the right the seed is shrivelled. Photos – Anne Cochrane Above: Allocasuarina thuyoides. Photo – Andrew Crawford
Germination of seeds DUpon wetting, seed of develop a mucilaginous Allocasuarina layer around the rim of the seed coat. This is likely to be an adaptive response to the environment, providing the germinating seed with an inbuilt source of moisture. Seed germinates readily without Below: Typical fruits of Allocasuarina. pre-treatment, although it is Photo – Andrew Crawford necessary to ensure that the seed you are trying to germinate is filled. Nicking a small section of the corner of the seed coat will reveal an endosperm. Seed can be direct sown or placed in dishes or pots for germination and emergence of seedlings should occur after two to five weeks. Seed may lose viability quickly once released from the cone unless kept dry and cool.
Germinating Allocasuarina D ramosissima seed. Photo – Anne Cochrane
Seed Notes 7 page Seed Notes for Western Australia
These Seed Notes aim to provide information on seed identification, collection, biology and germination for a wide range of seed types for Western Australian native species.
They have been written and compiled by Anne Cochrane, Manager of DEC's Threatened Flora Seed Centre. Concept by Grazyna Paczkowska. Designed by DEC’s Graphic Design Section.
The Seed Notes are available from www.naturebase.net
Top left: Allocasuarina thuyoides. Top right: Allocasuarina tortiramula. Above: Habitat of Allocasuarina ramosissima. Photos – Anne Cochrane Seed Notes are published by the Perth Branch of the Recommended reading Wildflower Society of Wilson, K. L. and Johnson, L. A. S. 1989. Western Australia (Inc.) Elliot, W. R. and Jones, D. L. 1984. Casuarinales Flora of Australia 3. 100–203. with assistance from Encyclopaedia of Australian Plants Suitable AGPS, Canberra. for Cultivation. Volume 2. Lothian Publishing, the Western Australian DMelbourne. Lotteries Commission and the Department Sharr, F. A. 1978. Western Australian Plant of Environment and Names and their Meanings. A Glossary. D Conservation (DEC). University of Western Australia Press, Perth. 2007501-0308-1
Seed Notes 7 page