Arabis alpina

About

Arabis alpina, the Alpine rock-cress, is a flowering plant in the family Brassicaceae, native to mountainous areas of Europe, North and East Africa, Central and Eastern Asia and parts of North America. In the British Isles, it is only known to occur in a few locations in the Cuillin Ridge of the Isle of Skye. It inhabits damp gravels and screes, often over limestone.

Summary from Wikipedia