Order: Verrucariales Family: Verrucariaceae
Species: Verrucaria macrostoma
Photos: On church wall, the Burren, Co. Clare, Ireland.
Well-developed, superficial, mid-brown thallus, darker in exposed locations, paler brown in shade. Rounded or lobed areoles often cracking into large secondary areoles. Areoles more/less subsquamulose. Black perithecia not leaving pits when decayed.
Found throughout Ireland on calcareous rocks, limestone and on mortar. Chemical reactions negative.
Similar: V. macrostoma f. furfuracea. Blastidiate.
Verrucaria macrostoma. BLS meeting, the Burren. April 2009