About Melastoma malabathricum subsp. malabathricum
Melastoma malabathricum subsp. malabathricum (often referenced here as Melastoma affine) grows as a shrub reaching up to 2 meters (6.6 feet) in height. Its leaves are ovate, 6 to 12 centimeters (2.5 to 4.5 inches) long and 2 to 4 centimeters (1 to 1.5 inches) wide, covered in fine hairs and marked with longitudinal veins. Flowers bloom in spring and summer, growing at the ends of branchlets. They are purple with five petals and five sepals, and have two distinct sets of stamens: five positioned opposite the petals, and five opposite the sepals. The stamens opposite the sepals have long anthers with a bilobed appendage at their base. This subspecies produces purple fruits 8 millimeters long; the fruits split open to reveal reddish to purple flesh holding many small seeds. Its common name 'blue tongue' comes from the edible purplish-black pulp inside the fruit capsules, which stains the mouth blue. This plant is distributed from the Indian subcontinent through Southeast Asia, Malaysia, and Indonesia into Australia. Within Australia, it occurs from the Kimberleys in Western Australia, across the Northern Territory and Queensland, and extends as far south as Kempsey on the mid north coast of New South Wales. It grows in wet areas of sclerophyll forest. In the Australasian region, it is an important pioneer species that colonizes disturbed wet-sclerophyll and rainforest habitats. It produces no nectar, and instead provides pollinators with large amounts of pollen, which must be extracted through pores on the anthers. It is pollinated by bees, particularly Xylocopa bombylans, X. aff. gressittii, Amegilla anomola, and Nomia species. Introduced honeybees outcompete native bees for pollen at its flowers, which negatively impacts the species' reproduction. This is a fast-growing, adaptable shrub that is sometimes grown in cultivation, and can be propagated by either seed or cuttings. In Indonesia, the plant is used to make grass jelly (cincau perdu). Its fruits ripen to dark gray, and contain edible purple pulp around the seeds that stains the mouth black, which is referenced in the genus name. In Indonesia and the Solomon Islands, sap or leaf extract is used as a herbal medicine to treat a range of conditions, including diarrhoea, burns, ulcers, wounds, piles, and thrush.
