Description: To understand the gist of this species, you should imagine Tephromela atra without discs and the centre of the thallus dissolved into a mist of blue-grey, minutely granular soralia. T. grumosa is K+ yellow and grows on friable siliceous rock surfaces, for example, sandstones, including man-made structures such as sandstone walls and old churches. In Ireland, it appears to be restricted to the north and north-east.

Key Identification Features:

• Thallus like that of T. atra but centre of thallus sorediate, very rarely with discs
• Spot tests K+ yellow only; on sandstone or similar textured siliceous rocks.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Tephromela grumosa at iNaturalist World Species Observations database.