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. Deeply immersed blackish-brown apothecia often with pale-grey pruina. Pits in rock are left when apothecia fall out. A black prothallus is sometimes present. 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