''Xanthorrhoea australis'', the grass tree, austral grasstree or blackboy, is an Australian plant. It is the most commonly seen species of the genus '' Xanthorrhoea''. Its trunk can grow up to several metres tall and is often branched. In certain Aboriginal languages, it is called ''bukkup'', ''baggup'' or ''kawee''.

Description

The main way to identify ''Xanthorrhoea'' is by looking at the cross-section of the leaves. In the case of ''X. australis'' the cross-section is a rough diamond shape, and the colour of the leaves is a bluish-green. The species usually develops a rough trunk which may be branched and coloured black, the result of bushfires. The trunk is able to grow up to over in height with a width of up to and may be branched. The bark is thick, rough and corky. The plant is very slow growing and trunks only start appearing after many years. The long, narrow leaves are crowded together at the tops of the trunks. ''X. australis'' takes several years to flower, and it does not always flower annually, but in the season after a bushfire it flowers prolifically. The flowers appear on a spear-like spike which can grow up to tall. The flowers, with 6 petals, usually cover – of the stem. The crown of leaves is almost spherical in shape, the point of each leaf perfectly marking the shape of the imagined sphere. The leaves crown the trunk in a crowded whorl of long, wiry leaves. They are arranged in a spiral, forming an erect tuft when young and spreading as they mature, with the oldest leaves dying and forming a hanging skirt around the trunk. The blue-green needle-like leaves are typically long and have a waxy coating. The leaves are softer and generally less rigid than other Xanthorrhoeas. Old leaves hang down forming a distinctive skirt-like feature that partly covers the fire-blackened trunk. ''X. australis'' flowers from July to December, but younger plants may flower in June. The common name ''grass tree'' is accurate as the trunks and branches of the tree varieties are literally made out of the leaf bases, not wood. Grass trees are often very long-lived with some estimated to be 350 to 450 years old.

Taxonomy

The species was first formally described by the

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

Robert Brown in 1810 as part of the work ''Prodromus Florae Novae Hollandiae''. The genus name '' Xanthorrhoea'' is taken from the Greek words ''xanthos'', meaning yellow, and ''rheo'', meaning to flow, a reference to the resin that is obtained from these plants. The species epithet ''australis'', meaning southern, refers to the distribution of the species.

Distribution

This species can be found in the states of

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

Australian Capital Territory The Australian Capital Territory (commonly abbreviated as ACT), known as the Federal Capital Territory (FCT) until 1938, is a landlocked federal territory of Australia containing the national capital Canberra and some surrounding townships. ...

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

and Victoria. It is regarded as the most widely distributed all of the ''Xanthorroea'' species. It is able to survive in poor soils, is intolerant to

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

and is highly susceptible to the soil-borne disease '' Phytophthora cinnamomi''.

Uses

Indigenous Australians Indigenous Australians or Australian First Nations are people with familial heritage from, and membership in, the ethnic groups that lived in Australia before British colonisation. They consist of two distinct groups: the Aboriginal peoples ...

soaked the flowering spikes in water to produce a sweet drink. The soft, white leaf bases were eaten as well as the growing point of the stem. The flower spike exudes a resin which could be used as an adhesive in the manufacture of tools and the stem used for the lower portion of a spear. Stems were also used to make a base for a fire-drill to start a fire. The resin was also collected and sent to commercial processors where it was made into lacquer for furniture of cabinet makers. In 1915 there was considerable consternation over the realisation that German agents had been buying “immense quantities of grass tree gum for the past quarter of a century”, presumably for the purpose of manufacturing explosives. The explosive containing grass tree resin was reported as more explosive than dynamite in experiments at the time.

References

Australian Native Plants Society (Australia) (ANPSA)

External links