Description: This is a crustose species characteristic of hard limestones, often in shady situations. It is easily told from other species by its finely cracked, blue-grey to silver-grey colour. The spherical discs (perithecia) are abundant and over three-quarters immersed in the thallus. It is common in areas with suitable habitat, especially on the limestones of western Ireland.

Key Identification Features:

• The thick, finely cracked, silver-grey thallus, abundant discs and the habitat strongly suggest this species
• The discs that are tiny flasks embedded in the thallus have a conspicuous concave depression at the top, which can be seen with a hand lens.

Original text submitted by Simon Davey

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

iNaturalist: Verrucaria coerulea at iNaturalist World Species Observations database.