Description: This pale grey crustose lichen, typical of nutrient-enriched field trees is characterised by fine, cylindrical or branched isidia that sometimes spread to cover the entire surface of the thallus, thus producing a textured, grey crust. It is C+ orange to red. These tests should always be done using fresh bleach. Discs are uncommon. It is a frequent species on the mature bark of well-lit trees in Ireland.

Key Identification Features:

• The patches of grey thallus packed with fine (<0.5mm diam.) isidia sometimes spreading to form a complete crust on wayside field trees should help separate it
• It can be separated from Ochrolechia turneri and Phlyctis argena by the positive C reaction.

Original text submitted by Simon Davey

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

iNaturalist: Ochrolechia subviridis at iNaturalist World Species Observations database.