Order: Pertusariales       Family: Megasporaceae Species: Circinaria contorta (Aspicilia contorta) Growth type crustose Photos: On concrete fences. Co. Cork, SW Ireland. Greenish-grey thallus with separate, convex areoles that later merge and become paler in colour. Prothallus indistinct. Apothecia are immersed black discs, often covered with bluish-white pruina, usually single in centre of each areole. Asci are 4-spored, spores simple, 20 x 11 µm. Epithecium olive-green, K+ orange-yellow. Thallus: Chemical reactions negative. Common on concrete, mortar and hard calcareous rocks, very tolerant of nutrient enrichment. Two sub-species; subsp. contorta and subsp. hoffmanniana, photographs below. Similar: Aspicilia calcarea

Aspicilia contorta. On concrete, Co. Cork. December 2011 and January 2012