Rhizocarpon tetrasporum Runemark

Lichenised. Poorly known taxon.
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: on siliceous rocks in the mountains; closely related to Rh. viridiatrum and Rh. oportense, this taxon is worthy of further study.
Italy: Piemonte; Valle d'Aosta;