Species: Verrucaria baldensis
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