Description: You will do best to search the edge of acid rivers and streams for this species. The brown, uneven, mottled non-gelatinous thallus produces its perithecial discs wrapped up in a conical outer layer (involucrellum) and a cuff of thallus. The spores are large, simple (26–32mm diam.). In Ireland, the lichen is widespread but local, western Atlantic areas mostly.

Key Identification Features:

• Brown, mottled thallus, never smooth or gelatinous when wet
• Perithecia with an involucrellum and cuff of thallus (sometimes this peels away with age); spores large to 32mm diam.; lake margins and sides of rivers and streams.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Verrucaria margacea at iNaturalist World Species Observations database.