Flora of Australia
These adaptations are common in species from the large and well-known families Proteaceae (Banksia), Myrtaceae (Eucalyptus - gum trees), and Fabaceae (Acacia - wattle).
Collision with the Eurasian Plate also led to additional South-east Asian and cosmopolitan elements entering the flora like the Lepidium and Chenopodioideae.
Hard leaves with a thick outer layer, a condition known as scleromorphy, and C4 and CAM carbon fixation which reduce water loss during photosynthesis are two common adaptations in Australian arid-adapted dicot and monocot species respectively.
In phytogeography, the area is considered a floristic kingdom (Australian kingdom), with the following endemic families, according to Takhtajan: Platyzomataceae (now included in Pteridaceae), Austrobaileyaceae, Idiospermaceae (now part of Calycanthaceae), Gyrostemonaceae, Baueraceae, Davidsoniaceae, Cephalotaceae, Eremosynaceae, Stylobasiaceae, Emblingiaceae, Akaniaceae, Tremandraceae, Tetracarpaeaceae, Brunoniaceae, Blandfordiaceae, Doryanthaceae, Dasypogonaceae and Xanthorrhoeaceae.
Other families with high occurrences are Poaceae, Fabaceae, Asteraceae, Orchidaceae, Euphorbiaceae, Cyperaceae, Rutaceae, Myrtaceae (specially Leptospermoideae) and Proteaceae.
[16] According to the scheme the most common vegetation types are those that are adapted to arid conditions where the area has not been significantly reduced by human activities such as land clearing for agriculture.
The terrestrial orchids occur across most of Australia, the majority of species being deciduous – their aboveground parts die back during the dry season and they re-sprout from a tuber when it rains.
The Myrtaceae is represented by a variety of woody species; gum trees from the genera Eucalyptus, Corymbia and Angophora, Lillipillies (Syzygium), the water-loving Melaleuca and Bottlebrush and the shrubby Darwinia and Leptospermum, commonly known as teatrees, and Geraldton wax.
The Asteraceae is well represented by its subfamily Gnaphalieae, which included the paper or everlasting daisies; this group has its greatest diversity in Australia.
Other families with flowering shrubs include the Rutaceae, with the fragrant Boronia and Eriostemon, the Myoporaceae with the Eremophila, and members of the Ericaceae with Victoria's Floral Emblem Epacris impressa.
Succulent stems are present in many of the Euphorbiaceae in Australia, though the best known members are the non-succulent looking fragrant Wedding bushes of the genus Ricinocarpos.
Carnivorous plants which favour damp habitats are represented by four families including the sundews, bladderworts, pitcher-plants from the Cephalotaceae, which are endemic to Western Australia, and the Nepenthaceae.
Most species are present in wetter mountainous areas consistent with their Gondwanan origins, including the genera Athrotaxis, Actinostrobus, Microcachrys, Microstrobos, Diselma and the Tasmanian Huon pine, sole member of the genus Lagarostrobos.
[30] Ferns prefer a cool and damp environment since water is required for reproduction, the majority of Australian species are found in bushland [clarification needed] and rainforest, there are aquatic, epiphytic (Platycerium, Huperzia and Asplenium), and terrestrial species including large tree ferns from the genera Cyathea and Dicksonia.
Many studies of algae include the cyanobacteria, in addition to micro and macro eukaryotic types that inhabit both fresh and saltwater.
[32] The bryophytes – mosses, liverworts and hornworts – are primitive, usually terrestrial, plants that inhabit the tropics, cool-temperate regions and montane areas; there are some specialised members that are adapted to semi-arid and arid Australia.
[35] Lichens are composite organisms comprising, in most cases, an Ascomycete fungus and a unicellular green alga, their classification is based on the type of fungi.
[36] The first Australian plants recognised and classified in Linnaean taxonomy were a species of Acacia and Synaphea in 1768 as Adiantum truncatum and Polypodium spinulosum respectively by Dutch philologist Pieter Burman the Younger, who stated they were from Java.
Later, both were found to be from Western Australia, likely to have been collected near the Swan River, possibly on a 1697 visit there of fellow Dutchman Willem de Vlamingh.
[37] This was followed by Cook's expedition making landfall at what is now Botany Bay in April 1770, and the early work of Banks, Solander and Parkinson.[who?]
Botanical exploration was enabled by the founding of the permanent colony at Port Jackson in 1788, and the subsequent expeditions along Australia's coastline.
[38] For example, the starchy roots of Clematis microphylla were used in western Victoria to make a dough that was baked, and the leaves of the plant were used as a poultice applied to skin irritations and blisters.
[citation needed] Until recently the macadamia nut and Tetragonia tetragonoides were the only Australian food plant species widely cultivated.
A few Australian native plants are used by the pharmaceutical industry, such as two scopolamine and hyoscyamine producing Duboisia species and Solanum aviculare and S. laciniatum for the steroid solasodine.
The changes since 1788 have been rapid and significant: displacement of Indigenous Australians disrupted fire régimes that had been in place for thousands of years; forestry practices have modified the structure of native forests; wetlands have been filled in; and broad scale land-clearing for crops, grazing and urban development has reduced native vegetation cover and led to landscape salinisation, increased sediment, nutrient and salt loads in rivers and streams, loss of habitat and a decline in biodiversity.
These protected areas include national parks and other reserves, as well as 64 wetlands registered under the Ramsar Convention and 16 World Heritage Sites.
