Click on map to open large map in new window
(Map updated: 11 August 2009)

This species is restricted to south-west Ireland where it grows in seepage tracks on sheltered siliceous rock near the coast. The cracked thallus is grey-brown and the spherical discs (perithecia) are black. Spores are persistently seven-septate, 37–52µm long, but only 3–5µm wide. It is this last feature which truly distinguishes it from P. guentheri var. guentheri which has wider spores as well as a greater variation in spore septa.

Key characteristics

• Grey-brown cracked thallus with black perithecia; spores seven-septate, narrow
• Seepage cracks in hard siliceous rocks; near the coast.

Original text submitted by Vince J. Giavarini