Cliffs and screes are found mostly around the coast and in the mountains in Wales. Cliff ledges and crevices provide a refuge for rare wildlife, notably for Peregrine falcons and iconic species of plant, such as the Snowdon lily (Gagea serotina) and yellow whitlow grass (Draba aizoides). Scree and boulder habitats can also be important for uncommon ferns, saxifrages, bryophytes and lichens.