Melastoma is a genus of flowering plants in the family Melastomataceae, placed within the order Myrtales. The genus comprises over 100 species, though some authorities suggest the total should be reduced through taxonomic revision. Its members are shrubs and small trees recognized especially for their showy, bright purple flowers, which have made several species popular ornamental plants around the world.
The native range of Melastoma spans a broad arc of the Old World tropics and subtropics: from India and Southeast Asia north to Japan, south to Australia, and eastward across the Pacific Islands. Species also occur in the Seychelles. This wide distribution reflects the genus's adaptability to a range of tropical and subtropical environments.
Several Melastoma species have proven capable of becoming invasive outside their native range. In Hawaii in particular, introduced species have established naturalized populations and pose ecological concerns. Within the genus, at least one species is known to produce sphaeraphides — crystal aggregates found in the endophloem and mesophloem of the plant, though absent from bark and leaves.
The genus belongs to the large and diverse family Melastomataceae, which is distributed pantropically and contains roughly 170 genera.
Distribution
Melastoma species are native to temperate and tropical Asia (from India and Southeast Asia north to Japan), south to Australia, across the Pacific Islands, and to the Seychelles. Several species have naturalized beyond their native range and are considered invasive in Hawaii and other island groups.
Ecology
Several Melastoma species are known for their invasive potential outside their native range, particularly in Hawaii, where introduced populations have become established and pose threats to native ecosystems.
Taxonomy Notes
The genus is placed in the family Melastomataceae, order Myrtales. Some sources indicate the total species count — often cited as over 100 — should be reduced following critical taxonomic revision. An additional species, Melastoma malabituin, was described in 2020.
