Order: Ostropales       Family: Graphidaceae Species: Phaeographis dentritica Growth type crustose. Photos: On mature Ash trunk. Ballingeary, Cork, SW Ireland. Thallus variable, light-grey to whitish, powdery, cracked or slightly granular. Immersed much-branched apothecia, often star-shaped. Lirellae with prominent carbonaceous margins, pruinose disc. The base of the exciple is closed, with the margin continuing under the disc. Spores (5-)7-9 septate, 30-50 x 6-10 µm. Occurs on smooth patches of shaded acid-barked trees. K+ yellow > red, C-, KC+ red, P+ yellowish-orange, UV- Similar: Phaeographis inusta and Phaeographis lyelli are K-, base of exciple closed, spores 3-5 septate. Phaeographis smithii is K+, base of exciple open, spores 5-7 septate

     
Phaeographis dentritica on Ash. Ballingeary area, Co.Cork. December 2008