Description: This crustose lichen grows on the vertical surfaces of exposed siliceous boulders, usually in windy sites in the mountains. It is always found growing on the surface of the leafy liverwort Gymnomitrion crenulatum which forms tight cushions that adhere like glue to the rock surface. T. thiospora has a small, scaly (squamulose) thallus comprising aggregations of rounded granules which are yellowy-green or yellow-tan in colour. The unfrosted discs are weakly convex. Very distinctive; western Ireland mainly.

Key Identification Features:

• On exposed acid boulders in mountains, always among cushions of the liverwort Gymnomitrion
• The thallus is scaly, the scales rolled into yellowy granules, which causes them to stand out against the background.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Toninia thiopsora at iNaturalist World Species Observations database.