Order: Pertusariales       Family: Pertusariaceae Species: Pertusaria pertusa Growth type crustose. Photos: Gougane Barra, Cork, SW Ireland. Identified by John Douglass Thick, slightly cracked greenish-grey thallus, often with a conspicuous zoned margin. 3-7 apothecia are produced from each wart-like protuberance. The asci are usually 2-spored. Common on tree bark, occasionally found on rocks. K+ yellow, C-, KC+ yellow, P+ deep orange, UV+/- pale orange. Similar: Pertusaria hymenea. Discs +/- open.

Above: Pertusaria pertusa grazed by slugs or snails. August 2009