Sarcogyne clavus (DC.) Kremp.

Sarcogyne clavus occurs in Europe and North America at a variety of elevations in full sun or partial shade on siliceous rock. It often occurs near waterfalls, along rivers, or on rock surfaces with periodic flushing during rainstorms like steep inclines as well as in under hangs. In the Czech Republic S. clavus is locally common especially in middle elevations and submontane regions (e.g. in the Brdy Hills). The species is easy to identify. It has an endolithic thallus and large lecideine apothecia up to 4 mm in width with a very crenulate margin.

Ascomycota → Lecanoromycetes → Acarosporales → Acarosporaceae → Sarcogyne