|Blue quandong, showing buttressed roots, in Nightcap National Park, Australia|
Elaeocarpus angustifolius is a large and fast growing rainforest tree, native to Australia, in the Elaeocarpaceae family. It is commonly known as Blue Quandong, Blue Marble Tree, Bracelet Tree or Blue Fig, although it is not closely related to the genus of figs.
Description and Distribution [Habitat]
Elaeocarpus angustifolius can be found in the subtropical rainforest regions of the eastern Australian states of Queensland and New South Wales. Its range extends to New Caledonia, the Northern Territory and New Guinea.
It is a large tree that can grow up to 50 metres tall, usually with an elaborate buttressed trunk and roots. The altitudinal range is from near sea level to 1100 metres.
In Australia, the tree tends to produce small greenish-white bell-shaped flowers between March and June, with the easily recognisable blue fruits forming in September to November. The flowers are composed of five feathery fringed petals and appear to droop. Trees usually mature (i.e. start flowering and fruiting) in their seventh year.
Blue Quandong fruits are typically spherical, between two and three cm in diameter, with skin a shiny brilliant blue and slightly wrinkled on the surface. The flesh is thin and pale green, surrounding a bumpy-textured hard rough woody "stone" (or endocarp) that has deep convolutions in its surface and contains up to five seeds. The fruits are attractive to birds and mammals, and are eaten whole by Australian brushturkey, cassowaries, woompoo pigeon and spectacled flying foxes. The seeds are passed undamaged and dispersed after digestion of the fruit.
The leaves are produced in clusters, and are finely-toothed, glossy, dark green, oblong-elliptical shaped and resemble the leaves of the Mango tree. 10-18 cm long, with the underside hairy and paler than the upper surface. Older leaves turn bright red to scarlet before falling.
Taxonomy and Naming
Elaeocarpus angustifolius has many common names, including Blue Quandong, White Quandong, Silver Quandong, Brush Quandong, Brisbane Quandong, Blueberry Ash, Indian Oil Fruit, Blue Fig, Genitri, Coolan, Cooloon and Caloon.
Cultivation and Uses
The Indigenous Australians used the fruits for bush tucker and ornament. The fruit pulp is edible when ripe, though sour and slightly bitter. It can be made into an edible paste by squashing it into a bark trough (or other suitable receptacle) filled with water. It is a popular ingredient in Aboriginal cuisine.
European settlers in Australia use the fruit for jams and pies. It can also be used for pickling. The fruit is reputed to have a vitamin C content higher than that of oranges.
The tree can grow up to eight metres in diameter, and to over 30 metres in height when mature. The wide-ranging buttress roots and size make the Blue Quandong tree unsuitable for suburban home gardens or planting near drains; this tree is more suited to larger acreage blocks and rainforest parks.
Timber and Seeds
The species is well regarded for its timber and as a key part in regenerating rainforest.
As an invasive species
"Elaeocarpus angustifolius [=grandis] (sapatua, siapoatua, siapatua, blue fig, blue marble tree, blue quandong), a native of Australia, is a forestry tree that is invading intact and secondary forests in Samoa." In other words this tree is an invasive species in Samoa.
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