Description: This small, pale to dark grey (greener when wet) crustose epiphyte can usually be located on nutrient-rich or dust-impregnated tree bark, often along waysides, rarely in woodland. As the discs are very tiny and Lecania-like they are the least noticeable aspect of the lichen. The thallus however, is minutely blistered with crater-like vesicles which later become scurfy and sorediate. In Ireland: widespread, except in the west where it is scarce.

Key Identification Features:

• Thallus crustose, pale grey to green, minutely blistered, scurfy-sorediate
• Discs brown, rounded or flat, swollen; spores polarilocular; thallus and discs K-.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Caloplaca obscurella at iNaturalist World Species Observations database.