Schismus is a small genus of annual grasses in the family Poaceae (order Poales), native to Africa and Eurasia. The genus comprises around five accepted species, with its center of diversity in the Mediterranean basin and southern Africa.
Plants in this genus are slender, low-growing grasses typically found in arid and semi-arid habitats, including desert margins, sandy soils, and disturbed ground. The two most widespread species — Schismus barbatus (Mediterranean grass) and Schismus arabicus — have expanded far beyond their native ranges and are now naturalized across much of the American Southwest, Mexico, Chile, Argentina, and parts of Australia, where they are considered invasive weeds in native desert ecosystems.
Schismus barbatus ranges natively from the Canary Islands east through the Mediterranean and neighboring regions to Tibet and south to South Africa. Schismus arabicus occurs naturally from Greece and North Africa through East Africa and Asia as far east as Xinjiang. Together these two species are commonly called Mediterranean grass in North America, where they can dominate disturbed soils and outcompete native annual plants.
The remaining species — S. inermis, S. scaberrimus, and S. schismoides — are confined to southern Africa (South Africa and Namibia).
Distribution
Schismus is native to Africa and Eurasia, with species occurring across the Mediterranean basin, Canary Islands, East Africa, the Arabian Peninsula, and central Asia east to Xinjiang and Tibet. South African species (S. inermis, S. scaberrimus, S. schismoides) are endemic to that subregion. Schismus barbatus and S. arabicus are naturalized across Australia, the western United States, Mexico, Chile, and Argentina.
Ecology
Schismus barbatus and S. arabicus are aggressive colonizers of disturbed, arid soils and are regarded as invasive species in North American desert ecosystems, particularly the Mojave and Sonoran deserts. They establish quickly after disturbance and can suppress native annual wildflower communities by competing for moisture and light in sandy or gravelly substrates.
