Millettia pinnata is a legume tree commonly found around Mauritius.
It was introduced from Asia in 1874 and cultivated at Pamplemousses Botanical Garden in 1880. It measures between 15 and 25 meters in height and has a large canopy which may spread. Its trunk is brown-grey and measures between 50 to 80 centimeters in diameter. It may be straight or crooked and its bark may be smooth or vertically fissured. The tree’s mature leaves are a glossy deep green and each branch bears an uneven number of leaflets – “odd-pinnate” or “imparipinnate”. Its flowers appear in small clusters of white, purple or pink which blossom throughout the year, after which it bears pods containing seeds; the seeds will germinate after the pod has fallen and rotted.
Millettia pinnata’s has an Asian native habitat, tropical and temperate. From India to Japan and Thailand, as well as north and north-eastern Australia and some Pacific islands, but can be found through much of the tropical world where it was introduced. M. pinnata is most commonly found in coastal areas, often along beaches or rivers and in thickets close to sea level.
It is an extremely resilient tree – withstanding temperatures slightly below 0°C to 50°C. It grows in most soil types and can survive total submergence in fresh water continuously for several months at a time, and its roots are tolerant to saltwater. It can withstand high rainfall environments as well as long periods of drought and intense heat and sunlight, with its dense network of lateral roots and its thick long taproot. The roots nodules promote nitrogen fixation, allowing a symbiotic process with bacteria which converts nitrogen from the air into ammonium. It is also a pioneer tree in freshwater flooded areas in parts of its native range.
The resilience of the species make it a strong competitor to native plants, particularly in riverine and coastal environments, which make it an invasive species. No management measure are presently known to exist concerning the tree.
Millettia pinnata is being cultivated for its seed oils which are used in biofuels. This plant also has many medicinal uses, for example; bactericide, stomach aches, tonic, used against fever, arthritis, bronchitis, herpes and rheumatism. It is also planted as an ornamental tree.