Order: Lecanorales       Family: Megalariaceae Species: Megalaria grossa Growth type crustose. Photos: Growing over moss on hazel. The Burren, W Ireland. BLS Burren meeting 2009 Thallus pale green-grey or whitish, +/- smooth, often with black prothallus. Large matt-black apothecia with thick shiny margins excluded as disc becomes convex. The hypothecium is dark blue-green, K+ green. Spores 1-septate. Isidia and soredia absent. West of Ireland in old woodland over moss on basic-barked trees e.g. ash, maple, lime, hazel. Thallus: Chemical reactions negative. Similar: M. pulverea Thallus K+ yellow, P+ red, yellow or negative

Megalaria grossa. BLS Burren meeting, April 2009