Order: Verrucariales Family: Verrucariaceae
Species: Verrucaria caerulea
Photos: On limestone, the Burren, Co. Clare, Ireland.
Thick, finely cracked thallus, pale-grey or bluish-grey, areoles sometimes translucent or white-pruinose. Perithecia three-quarters to completely immersed.
Occurs on hard, often shaded limestone, particularly in western Ireland. Chemical reactions negative.
Verrucaria caerulea. BLS meeting, April 2009