Description: Currently Ireland’s (and Britain’s) sole sorediate member of the genus, look out for it below overhangs and in sheltered outcrops of calcareous schistose-like rock. The crustose, pale grey-green thallus is composed of scattered areoles which dissolve almost entirely into coarse, ± stalked soralia (bright green when moist) which can often hide the spherical discs from view. The colourless, muriform spores (8/ascus) can attain a length of 50µm; the discs are protected by a well-developed involucrellum. In Ireland, it is very rare in north Donegal.

Key Identification Features:

• Only sorediate Polyblastia; soredia sometimes stalked
• Spores colourless; 8/ascus, to 50µm long.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Polyblastia efflorescens at iNaturalist World Species Observations database.