Buellia vilis Th. Fr.

Syn.: Buellia enteroleucoides (Nyl.) Arnold, Buellia modica (Nyl.) Lettau, Lecidea disciformis Nyl. var. enteroleucoides Nyl., Lecidea enteroleucoides (Nyl.) Lamy, Lecidea modica Nyl.
Lichenised.
Substrate: siliceous rocks
Altitudinal range: from the montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies) to the alpine belt (potential vegetation: treeless Alpine grasslands and tundras, to the lower limit of perennial snow and the equilibrium line of glaciers)
Note: a mainly arctic-alpine, probably circumpolar early coloniser of siliceous pebbles in windy situations, and of recently eroded granitic boulders; certainly more widespread in the Alps, but easily overlooked.
Austria: Tirol; Kärnten; Switzerland: Uri; Valais; France: Alpes-Maritimes; Haute-Savoie; Italy: Friuli; Trentino Alto Adige;