Buellia sororia Th. Fr.

Syn.: Buellia sororioides Erichsen
Lichenised. Poorly known taxon.
Substrate: siliceous rocks, intermediate rocks (such as calciferous schists)
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 species of the B. aethalea-group with a non-amyloid medulla and ascospores longer (mean c. 16 µm) than in B. aethalea, but thallus also K+ yellow, then red; on siliceous rocks inbetween other crustose lichens; described from Sweden and not generally accepted, probably widespread, but poorly documented in countries where it is treated as synonym of B. aethalea.
Austria: Tirol; Kärnten; Niederösterreich (incl. Wien);