Species: Graphina anguina
Photos: On Sycamore. Macroom, Co. Cork, SW Ireland.
Specimen identified by John Douglass
Thallus whitish-grey, slightly shiny and often wrinkled or cracked. Margin of immersed apothecia often slightly elevated, carbonaceous margin flat with narrow disc. Lirellae are short, serpentine, usually star-shaped and often pruinose.
Ascus 8-spored. Colourless muriform spores, 20+ cells, 7-11 transverse septa, 25-50 x 12-16 Ám. Micro photographs below.
Throughout Ireland on slightly shaded smooth-barked trees, often in secondary woodland or coppices. Chemical reactions negative.
Similar: Graphis scripta