The thallus of this granular-sorediate species forms dull-yellow green streaks or ‘flashes’ on dry acid tree bark. On conifers or dead standing pine trees the sight of it in otherwise lacklustre woodland, can be striking – like a beacon in the dark. Spot tests are negative. The related C. chrysophthalma has an immersed thallus. C. flavovirens has a scattered distribution in Ireland.

Key characteristics

• Forms striking, dull yellow-green streaks on dry acid-barked trees, especially dead conifers
• Related species are bright golden yellow in colour or have positive spot tests.

Original text submitted by Vince J. Giavarini