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Alstonia scholaris (L.) R. Br. 1810
pronounced: al-STOH-nee-uh skoll-AH-riss
(Apocynaceae – the oleander family)
common names: Milkwood, White Cheesewood, Dita Tree
This is a medium-sized to large evergreen tree that can attain a height of 35 m and a DBH of 1 m. The rough bark is light grey to grey, and when cut it is yellowish brown and exudes a large quantity of bitter-tasting milky sap. The species is widely distributed in Queensland, from Sarina to Thursday Island. It also occurs in New Guinea, south-east Asia, India and Sri Lanka.
The upper sides of the leaves are glossy, and the lower sides greyish. Leaves occur in whorls of 3 to 10, most usually 7; the petioles are 1 – 3 cm; the leathery leaves are narrowly obovate to very narrowly spatulate, the base cuneate, and the apex usually rounded. Lateral veins occur in 25 – 50 pairs, at 80 – 90º to the midrib.
The flowers, small and greenish yellow in colour, grow in cymes that are dense and pubescent; the peduncle 4 – 7 cm long. Pedicels are usually as long as or shorter than the calyx. The corolla is white and tube-like, 6 – 10 mm; lobes are broadly ovate or broadly obovate, 2 – 4.5 mm, overlapping to the left.
The species survives cyclones by shedding most of its branches, leaving only a bare pole standing. The crown subsequently regenerates. The reason that the regrowth occurs mainly from the central stem is quite unusual. Each internode is terminated by a whorl of 3 or more branches. A dormant bud below the terminal whorl of branches becomes active and produces a shoot that grows vertically and assumes the role of the main stem until the next whorl of branches is produced.
The leaves are a food source for the moth Parotis marginata.
Since ancient times, the tree has been used to make paper in India and in other parts of southern Asia. The wood was also used to make writing tablets (thus the specific scholaris). The timber from this tree is coarse in texture and straight-grained. The heartwood is white to cream with a very wide sapwood zone that is visually indistinct from the heartwood. This is a very soft timber, and will dress and mould to a smooth finish – but cutters and blades need to be sharp for successful working. It will readily accept paint, stain and polish, but prior filling may be necessary due to the coarse texture. It has some uses in construction, especially as mouldings, but also as fascia and barge boards. It is also used in joinery and turning. In Sri Lanka the wood is used for coffins. In Borneo it is used for fishing-net floats, and to make household utensils.
The bark of the tree contains alkaloids similar to those in quinine. At one time, a decoction of the bark was used to treat malaria and diarrhoea, as a tonic, febrifuge and anti-choleric, to stimulate menstruation, and to treat wounds. A decoction of the leaves was used to treat beriberi. In Ayurveda medicine in India, the leaves, bark and milky exudate are used in the treatment of fever (including malarial fever), abdominal disorders, dysentery and dyspepsia. The bark is also used in homeopathic medicine for its bitter and astringent properties, especially for chronic diarrhoea and dysentery.
In Theravada Buddhism, the Lord Buddha is said to have achieved enlightenment seated under this tree; but many tribal peoples believe that the tree is evil, and avoid it completely. They say that the tree is inhabited by evil spirits who will possess any person who walks or sits under it. They also believe that any person who sleeps under the tree will die. These beliefs have caused the tree to be spared much of the destruction that has faced a number of other species in India.
In Australia, the Aboriginal peoples used the latex to attach ceremonial garments to the skin before performing rituals.
One of the trees photographed is growing near the Picnic Bay Life-saving Club, and the other in a garden in Horseshoe Bay.
Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.
Photographs taken at Picnic Bay 2009, Horseshoe Bay 2017
Page last updated 8th December 2017