Order: Verrucariales       Family: Verrucariaceae Species: Bagliettoa baldensis (Verrucaria baldensis) Growth type crustose. Photos: On limestone rocks. The Burren, W Ireland. BLS Burren meeting 2009 Uncracked matt white or pale grey thallus with narrow dark prothallus. Very abundant small, almost immersed, perithecia which leave small pits in the thallus when they decay. Ostioles with 3 to 6 radiating cracks (visible with 20x lens). Host to Opegrapha rupestris Common, widespread throughout Ireland on hard limestone rocks and memorials and on mortar. Chemical reactions negative. Similar: Verrucaria hochstetteri. Larger perithecia

Verrucaria baldensis. BLS Burren meeting, April 2009