Order: Arthoniales       Family: Roccellaceae Species: Enterographa zonata (Opegrapha zonata) Growth type crustose. Photos: On shaded rock. Gougane Barra, Cork, Ireland. Identified by John Douglass Mosaic-forming cracked or smooth chocolate-brown thallus, often violet-tinged. Dark prothallus. Mauve-tinged dark-brown soredia on surface erode leaving paler patches. Apothecia rare. Chemical reactions negative. Occurs on damp, shaded siliceous rocks. Similar: Opegrapha gyrocarpa. Soralia C+ red.

Immediately above: Enterographa zonata (Opegrapha zonata) on granite erratic, the Burren, April 2009