Porpidia grisea Gowan

Lichenised.
Substrate: siliceous rocks
Altitudinal distribution: montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies)
Note: a silicicolous species resembling P. tuberculosa in the amyloid medulla and the presence of confluentic acid as a major substance, but esorediate and richly fertile, the apothecia usually with pruinose discs and the ascospores only up to 15 µm long; widespread in the Holarctic region from the Arctic to temperate-alpine zones but rare, with a single record from the Eastern Alps (Austria).
Austria: Salzburg;