Verrucaria endolithea Zschacke

Lichenised. Poorly known taxon.
Substrate: calciferous rocks
Altitudinal range: from the subalpine belt (potential vegetation: open, taiga-like forests dominated by Larix decidua and/or Pinus cembra and Rhododendron) 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 with a mainly endolithic to thin, continuous thallus indicated by grey patches, numerous minute ascomata (to 0.25 mm in diam.) forming hemispherically protruding black warts, a tightly adpressed involucrellum, 8-spored asci, and ellipsoid, simple ascospores (11-16 × 7-9 μm); on calcareous rocks in the lower alpine belt, only known from the type locality in the Eastern Alps (Switzerland).
Switzerland: Graubünden;