Australia’s Flora

Year 10

Banksia by Sydney Parkinson (1759-68). Image courtesy of National History Museum, London.

• Australia’s distinctive flora dates back to a time when the continent separated from the rest of Gondwanaland: about 30 to 40 million years ago.

• Since then it has evolved in isolation.

• As a result, 80% of all Australian plant species are endemic.

Endemic: Flora and Fauna species that do not occur naturally anywhere

else in the world.

Australia’s Flora

Australia’s Dominant Vegetation

Eucalypt

Acacias

Casuarinas

Hummock GrassesGrass Trees Banksias

Eucalypts• One of the most dominant and abundant flora

species in Australia is that of the Eucalypt.

• Australia’s eucalypts are well adapted to the conditions in which they live.

• Their small, hard, leathery and spiny leaves are

an adaptation to low- nutrient soils and dry conditions.

• Plants whose leaves are adapted in this way are referred to as sclerophylls

There are 4 main types of Eucalypt forests in Australia:

• Wet sclerophyll forests- These generally occupy moist gullies and the southern aspect of hillsides in areas with relatively high rainfall.

• Dry sclerophyll forests-This vegetation type has specifically evolved to suit the low-nutrient soils, to withstand drought and to regenerate after fire. This type of forest is a typical example of ‘the Australian Bush’ as most of us know it.

• Eucalypt woodlands-Australia’s woodlands are a combination of Eucalypts and grasslands; the mix is determined by the local conditions of aspect, soil and topography.

• Mallee woodlands-Mallees are stunted multi-stemmed eucalypts growing as small trees, which are adapted to drought and fire. Most Mallee country has now been cleared for agriculture.

Non- Eucalypt vegetation types• Acacias are almost as widespread as eucalypts. They

dominate in drier areas.

• Mulga occupies about 20% of the continent.

• Casuarinas have a pine like appearance growing often along riverbanks and creeks

• Hummock grasses occupy arid and semi arid areas.

Rainforests• Rainforests once covered

the whole of the continent.

• Today they cover just 0.25 %.

• As the continent drifted to the north and the continent’s climate became drier, the rainforest vegetation retreated to the isolated pockets of land where rainfall was at least 600mls a year and the risk of fire was minimal.

Flowering Plants• Australia’s long period of

isolation has also resulted in it having some of the worlds most exotic and spectacular flowers.

• The international demand for these flowers has resulted in an export trade worth at least $40million a year.