Haresfoot clover (Trifolium arvense) is a species of clover you will find in dry, sandy places where there is little grass, or only thin grass, to compete with. It can grow in quite harsh conditions being found even on sand dunes apparently although I have not encountered in quite such an extreme environment.
It is a low growing plant with an oval shaped flower, most clover flower heads are much more rounded. The flowers do actually look hairy or fluffy so it is easy to see how the common name was derived. The species flowers from June to August but each individual flower head does not last very long.
Like most members of the clover family, indeed much of the wider pea family, it enriches barren soils by fixing nitrogen which helps other crops grow so it has been planted on such soils with other crops so as to improve crop growth. Haresfoot clover itself has also been sewn as a fodder crop for sheep and goats in some places.