Sagina procumbens

Sagina procumbens (procumbent pearlwort) is a species of flowering plant in the family Caryophyllaceae, native throughout Europe, most of western and central Asia, and northwest Africa. It is a common weed in many environments, and can be found in wild and disturbed habitat, especially moist areas. It can frequently be seen growing in lawns or in cracks in pavements, particularly in block paving, where it resists human trampling well, and is also common in flower pots....read more on Wikipedia.