Description: This is a specialist lichen of smooth-barked trees (especially hazel) in sheltered western woodlands. It differs from other Irish Thelotrema lichens in the numerous, flattened, glazed discs which appear jagged and disintegrating around the edges. The creamy white thallus can spread to dominate the bark along with Bactrospora homalotropa and other western Graphidion species. The spores are septate (never muriform). On hazel, rowan, holly, willow etc. Western Ireland.

Key Identification Features:

• Discs flattened; the veiled surface split open like a star and frosted over
• Mostly on hazel in wet, oceanic woodlands and by western lough shores.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Thelotrema subtile at iNaturalist World Species Observations database.