Antirhea borbonica is a small tree typically measuring under 6 meters. The dark green leaves occur in whorls of three. The stalks and underside of leaves typically have hair, and often have domatia - small chambers inside the plant or made by hairs on leaves that offer shelter to arthropods. Its trunk measures around 30 centimeters in diameter and its bark is smooth and grey in colour. The flowers are small, white, tubular with four lobes and are scented. The tree produces small black fruit, which each bear one or two seeds protected by a reddish pulp.
Endemic to Mauritius it is found in the intermediate and upland forests. The species is variable and in altitude often have smaller leaves. The domatia under the leaves shelter mites that protect the tree by repelling other parasites such as insects, phytophagous mites, other mites and fungi. A. borbonica is a species typically requiring light for germination, and as such is considered a ‘nomad’, fast growing, light-demanding species characteristic of large gaps in the forest, forest edges and clearings. It is thus also part of a group of pioneer species and can support ecological restoration in degraded areas.
A. borbonica is a species of ‘Least Concern’ on the IUCN Red List of Threatened Species, A. borbonica grows in the National Parks of Mauritius where its presence in sufficient numbers justifies this status. However, the size of its population is decreasing due to the invasion of exotic species and the loss of its habitat.
The tree has many medicinal properties, it is an astringent, its crushed leaves are haemostatic, helping to stop bleeding, while a bark and leaf infusion helps to treat diarrhea and fever.
A local named Lousteau discovered the species and it is from his name that the vernacular name originates.
The Ecology of Trees in the Tropical Rain Forest – I. M. Turner
Rachel Atkinson and Jean-Claude Sevathian, A guide to the plants in Mauritius, (Mauritius: Mauritian Wildlife Foundation, 2005), 80