pronounced: mill-ETT-ee-uh pin-NAH-tuh
pronounced: pon-GAY-mee-un pin-NAH-tuh
Millettia is named for J.A. Millett, a French botanist who worked in China in 1726, and collected the first specimen; pinnata is from the Latin pinnatus, feathered, winged (the leaves are pinnate); in the synonym, Pongamia is from Pongam, the Malabar vernacular name of the tree. There is actually some doubt as to which is the correct species name - authorities are divided.
This is a native of tropical and temperate Asia, including parts of China, Japan and Malesia, and is also found in Australia and some of the Pacific Islands. On Magnetic Island it is mostly found along the creek banks.
The tree can grow to between 15 and 25m in height, with a large canopy that spreads about the same distance in width. It may be deciduous for short periods. The leaves are a soft, shiny burgundy at first, and mature to a glossy deep green.
The flowers are the usual pea-shape, and vary from pink to mauve. They are followed by indehiscent brown pods: these are flattish and woody.
The tree is well adapted to arid areas and has many traditional uses. It is often used for landscaping purposes as a windbreak or for shade, due to its large canopy and showy flowers. The fallen flowers are gathered and used as compost for plants requiring rich nutrients. The bark can be used to make twine or rope, and it also yields a black gum that has historically been used to treat wounds caused by poisonous fish. The timber is beautifully grained, but is difficult to work with tools, as it easily splits; so it is mainly used for firewood, posts, and tool handles.
Although all parts of the plants are toxic, and will cause nausea and vomiting if eaten, the fruits and sprouts, along with the seeds, are used in many traditional remedies. Juices from the plant, as well as the oil, are antiseptic and resistant to pests. Oil made from the seeds, known as honge oil, has been used as lamp oil, in soap making, and as a lubricant, for thousands of years.
The tree is heavily self-seeding, and can also spread lateral roots up to about 9 m. If not managed carefully it can become an invasive species; but its dense network of lateral roots makes it useful for controlling soil erosion, and for binding sand dunes.
The seed oil has been found to be useful in diesel generators, and it is now in use in a number of rural Indian villages, after a simple processing, in diesel generators to supply electricity to run water pumps and electric lighting. Research is currently under way in Queensland to facilitate the commercial cultivation of the tree and the use of the oil for the production of biofuel.
Pongamia is a food plant for the larvae of several butterflies and moths, including:
• the Citrus Leafminer Phyllocnistis citrella;
• the Brown Awl Badamia exclamationis;
• the moth Echiomima mythica;
• the Dark Cerulean Jamides phaseli; and
• the Common Banded Awl Hasora chromus.
