Species: Caloplaca citrina sens lat.
Photos: On coastal rocks. Snave, Cork, SW Ireland.
Yellow to greenish-yellow or orange thallus comprised of minute, sometimes lobed, granules covered by orange soredia. Yellowish-orange apothecia with sorediate paler margin. Very variable.
K+ crimson / purple.
Very common on walls, mortar and calcareous rocks, also sometimes found on bark, moss and soil.
Similar: Caloplaca flavocitrina
Caloplaca citrina. Snave, Co.Cork. September 2009