M. malabathricum is native to the Marianas and Caroline Islands. Present on Pagan, Alamagan, Saipan, Guam, Palau (Babeldaob, Koror, Ngarakabesang, Malakal, and Aulupse'el), Yap, Pohnpei, and Kosrae (PIER 2006). It is listed as a noxious weed in Florida and North Carolina (USDA-ARS 1998 in Starr et al. 2003). M. candidum was previously recognized as M. malabathricum by sensu Hawaiian botanists (Starr et al. 2003). In Hawaii, M. candidum was previously called and sometimes still referred to as Malabar melastome and Indian rhododendron, which are common names for M. malabathricum (Starr et al. 2003).
M. sanguineum (fox-tongued melastoma, red melastome) is native to Java, Sumatra, Vietnam, southeastern China, Burma, Thailand, Malaysian Pensinsula, Borneo, Moluccas, and Indochina, growing in disturbed forests, along streams and roads, in open places and savannas up to 2,300 m (7,546 ft) elevation (Starr et al. 2003). It can be easily mistaken as M. candidum without careful examination. M. sanguineum was also introduced as an ornamental shrub and cultivated in the Maui Island of Hawaii. It has 6 petals, with branches and petioles sparsely covered with spreading, smooth hairs 5-15 mm long. In contrast, M. candidum has 5 petals, with branches and petioles densely covered with a mixture of appressed, short, laciniate scales 0.5-1 mm long (Wagner et al. 1999 in Starr et al. 2003). M. sanguineum will likely be added in the target species list for eradication by the Maui Invasive Species Committee (MISC) in the near future (Starr et al. 2003).
Tibouchina urvilleana may be confused with M. candidum and M. sanguineum. Both Melastoma spp. differ from Tibouchina urvilleana in having yellow staminal appendages and hypanthial pubescence that consists of basally flatttened, incurved hairs of overlapping lanceolate scales (Wagner et al. 1999 in Starr et al. 2003).