Order: Pertusariales       Family: Pertusariaceae Species: Pertusaria flavicans Growth type crustose. Photos: On coastal rock. Zetland Pier, Co. Cork, SW Ireland. Photographs confirmed by John Douglass. Thick, smooth, warted or cracked-areolate thallus, yellow or yellowish-green. Numerous granular soralia, usually paler in colour than thallus. Apothecia rare, the dark ostioles with thick margins. Found on siliceous upland and coastal rocks. Thallus: K-, C+ orange, KC+ orange, P-, UV + orange. Soralia: C+ orange, UV+ bright orange

Pertusaria flavicans showing KC+ orange reation. September 2009