LICHALP

Acarospora impressula Th. Fr.

Syn.: Acarospora atrata Hue

Lichenised.

Substrate: siliceous rocks, metal-rich siliceous rocks

Altitudinal range: from the submediterranean/colline belt (potential vegetation: mixed deciduous forests dominated by Quercus and Carpinus) 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: an arctic-alpine to boreal-montane, probably circumpolar species found on metal-rich rocks and roofing slates, more rarely on weakly calciferous siliceous rocks, usually in upland areas, with optimum above treeline; probably overlooked and more widespread in the Alps.