Cenchrus echinatus is a species of grass known by the common names southern sandbur, spiny sandbur, southern sandspur, and in Australia, Mossman River grass. It is native to North and South America. It is a clump-forming annual grass growing up to tall. The leaves occur with or without hairs and measure up to wide. The ligule is a fringe of hairs. The grass has barbed burrs of long.
In Australia it forms an invasive weed in coastal situations.
The species is invasive in New Caledonia, Tahiti, and Rarotonga.