Description: This is mostly a crust of wooden railings bounding the long drives of old estate properties, but it will just as easily colonise wooden bollards in towns and picnic tables set out on grassy lawns by the sea. The green or blue-green thallus is composed of flattened, granular areoles linking together like a jigsaw to form a continuous crust. Powdery grey-green to dark blue-green soredia is often present on the surface. A dab of fresh bleach turns it red. Northern half of Ireland, mostly.

Key Identification Features:

• Green-blue thallus of flattened, jigsaw piece-like areoles coated in green soredia; on the tops of wooden rails, posts and bollards
• C + red thallus.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Trapeliopsis flexuosa at iNaturalist World Species Observations database.