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Aleurites moluccanus (L.) Willd. 1805
pronounced: al-yoor-RY-teez moll-oo-KAN-uss
(Euphorbiaceae— the spurge family)
common names: Candlenut, Indian Walnut
Aleurites is from the Greek αλευρον (aleuron), wheaten flour, referring to the powdered appearance of new growth; moluccanus means of or from the Molucca Islands. There is some doubt as to the correct ending of the specific - Kew gives it as -a rather than -us.
We cannot be certain where this tree originated, as it was from very early times spread by humans. It is widely distributed throughout the tropics, and, in Australia, is found on Cape York Peninsula and in north-east Queensland from Daintree north, and in an isolated patch in central Queensland.
The trees grow from near sea level to about 800 m in altitude. This is a fast-growing tree, often growing in disturbed rainforest but also found in well-developed rainforest and gallery forest. The tree photographed has been planted in the grounds of the Arcadia Hotel.
The tree grows to a height of between 15 and 25 m, with wide-spreading or pendulous branches. The bark is usually divided into large plates.
The leaves are pale green, simple, and either ovate, tri-lobed, or (rarely) five-lobed, with an acute apex. They are large, up to 20 cm long, or even a little more, and up to about 13 cm wide. Oil dots are visible with a lens. There are one or two conspicuously raised green or almost black glands on the upper surface of the petiole near its junction with the leaf blade. The underside of the leaf blade is clothed in brownish stellate hairs or scales. Young shoots and the terminal buds are densely clothed in cream or brown hairs, many of which are stellate.
The fruit is depressed spherical, 4-6 cm across, usually 2-lobed, sometimes reduced to one. The nut is round, up to about 4 cm in diameter; the seed inside has a very hard seed coat and a high oil content, which allows its use as a candle.
In ancient Hawaii, the nuts were burned to provide light. They were strung on a row on a palm leaf midrib, lit on one end, and burned one by one, taking about a quarter of an hour per nut. This enabled them to be used as a measure of time. Hawaiians also extracted the oil from the nut and burned it in a stone lamp with a wick made of kapa cloth. They also had many other uses for the tree:
- leis were made from the shells, leaves and flowers;
- ink for tattoos was made from charred nuts;
- the oil was used to make a varnish;
- fishermen would chew the nuts and spit them out on to the water to break the surface tension and remove reflections. so that they could see underwater better;
- a red-brown dye was made from the inner bark and used to dye cloth and cordage;
- a coat of oil was applied to fishing nets to help preserve them;
- the seats and gunwales of outrigger canoes were made from the timber;
- smaller canoes used for fishing were made from the trunks.
In Tonga, even today, ripe nuts are pounded into a paste and used as soap and shampoo.
Dead wood of the tree is eaten by a larva of a coleopteran called Agrianome fairmairei. This larva is eaten by some peoples. It is reported that Australian Aborigines ringbarked the trees to allow the grubs to flourish.
The candlenut has long been a source of food for Aborigines, Pacific islanders, and the peoples of south-east Asia. The seeds must be roasted before eating, as raw nuts have a purging effect. Care should be taken, as the very similar-looking Aleurites rockinghamensis has seeds that are quite toxic.
The timber is silvery white, very plain, and, although light and soft, is fairly tough. When draining boards were of wooden construction and kitchen shelves were often left unpainted, candlenut was popular for the purpose, because it retained its whitish colour for a long time. Today, the timber is mainly used for packing cases.
Photographed in Arcadia, 2018
Page last updated 5th February, 2018