Order: Pertusariales Family: Pertusariaceae
Species: Ochrolechia subviridis
Photos: On old Oak. Glengarriff woods, Co. Cork, SW Ireland.
Identified by Andy Acton
Smooth to warted, whitish to grey or grey-green thallus with zoned white margin. Extensive patches of short, soft isidia, forming +/- continuous crust. Isidia erode easily and can break down to granular soredia. Apothecia rare, pinkish, often pruinose, discs with isidiate margins. Isidia K-, C+ red, KC+ red, P-, UV+ glaucous
Occurs on well-lit, nutrient-rich bark of mature deciduous trees.
Similar: Pertusaria coccodes, thallus K+ yellow going red.
Ochrolechia subviridis April 2010