Order: Lecanorales Family: Physciaceae
Species: Rinodina sophodes
Photos: On deciduous twig. Gougane Barra, Cork, SW Ireland. Left identified by John Douglass
Pale grey to olive-brown thallus forming small, irregularly cracked patches, usually with a dark prothallus. Apothecia are immersed, sometimes becoming sessile. Discs dark-brown to black, remaining flat with thick white margins. Asci are 8-spored, the spores brown, 1-septate, 13-19 x 6-9 Ám. Microscope photographs below.
Usually occurs near leaf and girdle scars on smooth-barked twigs, often associated with Ash. Widespread, but most frequent in upland and exposed areas. Chemical reactions negative.
Similar: Rinodina olea. Most frequent Rinodina species on rock and man-made substrates, also occurs on wood and bark.