Order: Lecanorales Family: Rhizocarpaceae
Species: Rhizocarpon lecanorinum
Photos: On acidic upland rock. Ballingeary area, Cork, SW Ireland.
Identification very uncertain, needs confirming or correcting
Bright-yellow or slightly greenish-yellow thallus with +/- crescent-shaped areoles surrounded by black prothallus. Black apothecia are approx 1mm diam with epithecium pale green-brown, K-.
Occurs on metal-rich, upland siliceous rocks, walls and roofs.
Medulla K+ yellow, P+ orange
Similar: R. geographicum
Rhizocarpon lecanorinum. Ballingeary area, Co. Cork. May 2009