Description: Search for this lichen on basic rock in upland areas where the first sign of such a species will be prominent dots on the surface of the rock. The dots (perithecia with a distinct outer shell or involucrellum) grow from a thin, grey to brown thallus. When squashed and examined under a microscope the discs will be seen to contain colourless, muriform spores that are 21 to 45µm long. In Ireland, the species is poorly known.

Key Identification Features:

• Thallus thin: grey-brown; discs to 0.6mm diam.; with a well-formed involucrellum
• Spores colourless 21–45µm long.; basic rocks in the uplands.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Polyblastia cupularis at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Polyblastia cupularis at iNaturalist World Species Observations database.