Astrebla is a small genus of four xerophytic grasses in the family Poaceae (order Poales), endemic to Australia. They are commonly known as Mitchell grass, after the Scottish explorer Thomas Mitchell (1792–1855), who first collected a specimen near Bourke in New South Wales.
The four species — Astrebla pectinata, A. lappacea, A. squarrosa, and A. elymoides — are among the most ecologically significant grasses in inland Australia. They dominate vast areas of the continent's arid and semi-arid interior, thriving on heavy clay soils that many other grasses cannot colonise. Their typical rainfall range is 200–600 mm per year, though they also establish in low-rainfall depressions where water concentrates after rain events, such as in Sturt's Stony Desert.
Mitchell grasses are deep-rooted perennials capable of entering dormancy during prolonged drought, which allows them to survive extended dry periods and rapidly regrow once rainfall returns. In favourable conditions they form dense clumps reaching about one metre in height, creating structural habitat for a range of Australian fauna including mammals.
Etymology
The common name "Mitchell grass" commemorates Scottish explorer Thomas Mitchell (1792–1855), who collected the first known specimen near Bourke in New South Wales during his Australian expeditions.
Distribution
Astrebla species are endemic to Australia, primarily occupying the arid and semi-arid interior on heavy clay soils. They occur across regions receiving roughly 200–600 mm of annual rainfall, and extend into lower-rainfall areas such as Sturt's Stony Desert where water concentrates in topographic depressions after rain.
Ecology
Mitchell grasses are the dominant ground cover across much of Australia's inland clay plains. Their deep root systems and drought-dormancy strategy allow survival through extended dry periods, while the dense clumps they form when active provide structural habitat for native mammals and other organisms.
