Order: Pyrenulales       Family: Pyrenulaceae Species: Pyrenula occidentalis Growth type crustose. Photos: On hazel. Cathair Chomáin, the Burren, W Ireland. BLS Burren meeting 2009 Yellow-brown to creamy orange thallus with brownish flecks. Pseudocyphellae absent. Perithecia to 0.6mm. Occurs mainly in western half of Ireland on smooth-barked trees in damp, very sheltered sites. K+ yellowish and purplish in parts, P+ orange, UV+/- yellow

Pyrenula occidentalis. BLS Burren meeting, April 2009