Melinis is a genus of grasses (family Poaceae, order Poales) native to Africa and Arabia. The genus name derives from the Greek meline, meaning "millet." Melinis grasses are annuals or perennials, typically growing between 30 centimetres and a metre in height. They produce open, branched inflorescences bearing small spikelets that in some species are densely clothed in silky white or pink hairs, giving the plants a distinctive ornamental appearance.
The genus is primarily an African group, with its native range spanning sub-Saharan Africa, the Arabian Peninsula, and adjacent regions. Two species have become significant outside their native range. Melinis repens (rose Natal grass or Natal red top) is native to southern Africa and is now established as an introduced weed across North America and Australia. Melinis minutiflora (molasses grass), native to an arc from central Angola to Cameroon and the highlands around the Ruwenzori Mountains and Mount Kenya, was deliberately introduced to Brazil around 1812 and to Hawaii around 1900 as a livestock fodder grass, and has since become invasive in tropical regions across South America, the Pacific Islands, and beyond.
Both invasive species are noted for their role in fire ecology. Molasses grass in particular is brittle and burns readily, fuelling a self-reinforcing grass/fire cycle: after a wildfire it rapidly recolonises disturbed ground, builds up a flammable fuel load, burns again, and outcompetes native vegetation — a pattern documented in the Brazilian Cerrado, Hawaii, and Australia. Taxonomically, Melinis was formerly more broadly circumscribed; many species have since been transferred to the related genus Tricholaena.
Etymology
The genus name Melinis is derived from the Greek word meline, meaning "millet," a reference to the grass-like, grain-bearing character of these plants.
Distribution
Melinis is native to sub-Saharan Africa and Arabia. Melinis minutiflora (molasses grass) is native to an arc from central Angola and Cameroon through the east African highlands near the Ruwenzori Mountains and Mount Kenya. Melinis repens (Natal grass) is native to southern Africa. Both species have been widely introduced outside Africa and are now naturalized or invasive in tropical and subtropical regions of the Americas, Hawaii, and Australia.
Ecology
Molasses grass (Melinis minutiflora) is ecologically notable for its role in the grass/fire cycle. It establishes rapidly in disturbed habitats after wildfire, accumulates a brittle, easily ignited fuel load, and increases fire frequency in areas where it has invaded — including the Brazilian Cerrado, Hawaii, and Australia. This cycle suppresses native plant communities and reduces local biodiversity. Melinis repens is similarly regarded as a noxious weed in North America and Australia, where it displaces native vegetation.
Taxonomy Notes
Melinis was formerly more broadly defined and included numerous species now considered better placed in the related genus Tricholaena within the family Poaceae. Under current circumscription, approximately 23 species are accepted in the genus.
