Order: Verrucariales       Family: Verrucariaceae Species: Verrucaria caerulea Growth type crustose. 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