Order: Lecanorales       Family: Psoraceae Species: Protoblastenia calva Growth type crustose. Photos: On limestone rocks. The Burren, W Ireland. BLS Burren meeting 2009 Smooth, cracked, white or pale-grey, +/- immersed thallus. Large (to 1.5mm), convex, deep-orange apothecia in shallow pits. Only occurs on hard limestone, scattered distribution in Ireland. Apothecia K+ crimson Similar: P. rupestris. Common on mortar, calcareous rocks. Protoblastenia lilacina, apothecia K- or only very weak reaction

Protoblastenia calva. BLS Burren meeting, April 2009