Melastoma affine, also known by the common names blue tongue, straits rhododendron or native lassiandra, is a shrub of the family Melastomataceae.

Distributed in tropical and sub-tropical forests of India, South-east Asia and Australia, it is a plant of rainforest margins.

Appearing in spring and summer, the flowers occur on the ends of branchlets and are purple with five petals and sepals.

[8] M. affine is important as being a pioneer species that colonises disturbed wet-sclerophyll and rain forest habitats in the Australasian region.

[14] It produces no nectar - giving pollinators large amounts of pollen instead, which must be extracted through pores on the anthers.

[17][18] Sap or an extract from the leaves is used as a herbal medicine against a number of conditions including diarrhoea, burns, ulcers, wounds, piles and thrush in Indonesia and the Solomon Islands.