Order: Lecanorales       Family: Porpidiaceae Species: Clauzadea immersa Growth type crustose. Photos: On limestone. Teampall Chronain, the Burren, Ireland. BLS Burren meeting 2009 White to pale-grey thallus, the deeply immersed blackish-brown apothecia often with a pale-grey pruina and leaving pits in the rock when they fall out. A black prothallus is sometimes present. Spores are simple, 10-15(-19) × (6-)7-8(-9) µm, warted when mature. Pycnidia frequent. Thallus chemical reactions negative, hymenium I+ pale blue. Found throughout Ireland, can be locally frequent on hard, well-lit limestone and also occurs on church memorials.

Clauzadea immersa. BLS Burren meeting, April 2009