Order: Teloschistales Family: Teloschistaceae
Species: Caloplaca cerinella
Photos: On Ash twig. Ballingeary, Co. Cork, SW Ireland.
Identification confirmed by B. Coppins
Thin, smooth, grey to white thallus forming small patches or +/- immersed. Very small closely grouped apothecia, discs pale yellow to orange with paler persistent margins. Asci are (8-)12-16 spored, the spores polarilocular, 10-13 x 6-7 Ám, the septum 3-5 Ám wide, 1/4 - 1/2 spore length. Microscope photograph below.
Thallus K-, apothecia K+ red-purple
Inconspicuous, possibly often overlooked on bark of twigs and small branches of Ash and Elder.
Similar: C. cerina. Larger discs, asci 8-spored.