Description: The warm brown or grey (in shade) tones of this crustose lichen coating the surfaces of siliceous rock outcrops and boulders in mountain country is one of the most characteristic species of wild Ireland. An experienced eye may be needed to distinguish this species from its close relatives, despite its abundance, but even at close quarters one can sense there is something distinctive about the black ring of prothallus which encircles it when forming mosaics and the rounded, dark brown discs with a pale thin margin. The chemical that will distinguish most collections for certain is Pd. In F. cyathoides the thallus is Pd+ red. It is Pd+ yellow in the browner F. lygaea and Pd- in the greyer F. kochiana; widespread. Throughout upland Ireland.

Key Identification Features:

• Warm brown thallus with rounded, dark brown discs and a black border
• Forms extensive mosaics on upland acid rocks; thallus Pd+ red.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Fuscidea cyathoides at iNaturalist World Species Observations database.