Order: Arthoniales Family: Roccellaceae
Species: Lecanactis abietina
Photos: Glengarriff woods, Co. Cork, SW Ireland.
Identified by Andy Acton
Thallus whitish to dark grey, thin or effuse. Numerous scattered pycnidia with white-pruinose tips, the pruina C+ red. Often infertile, when present the apothecia are brown and usually thickly grey-green pruinose, the spores 3-septate.
Thallus K-, C-, KC-, UV+ yellow or glaucous grey. Pruina K-, C+ red
Widespread on the dry, shaded side of acid-barked trees in mature woodland. Sometimes on mosses under overhanging acidic rocks.
Similar: Lecanactis subabietina, pruina K+ yellow,
Opegrapha vermicellifera, all chemical reactions negative
Lecanactis abietina March 2010