Order: Verrucariales       Family: Verrucariaceae Species: Verrucaria viridula Growth type crustose. Photos: On limestone. Teampall Chronain, the Burren, W Ireland. BLS Burren meeting 2009 Variable. Thallus usually superficial and areolate, normally pale brown but can be whitish, grey or green-grey. Thallus is sometimes +/- immersed and then appears as brown flecks on substrate. The large perithecia are half to completely immersed. Occurs on calcareous rocks, limestone, mudstone, mortar, brick and occasionally on soil. Common in both natural and man-made habitats. Chemical reactions negative.

Verrucaria viridula. BLS Burren meeting, April 2009