Vulpia myuros
Vulpia myuros, the annual fescue, or rat's-tail fescue, is an annual flowering plant in grass family Poaceae. It was probably originally native to Eurasia, but it can now be found nearly worldwide as a naturalized species.
In the United Kingdom it forms dense, even swards of fine, hair-like stems in recently disturbed habitats. It is often eventually displaced by perennial grasses.