Description: This glamorous, rosette-forming, foliose lichen with a smooth, blue-grey thallus and orange-brown fruits is not hard to identify, as it lacks both isidia and soredia. The minute, finger-like lobes show up well against the dark, hairy, almost black matted underside (hypothallus). It is especially frequent in mature willow swamp and hazel coppice as well as on mature ash trees in the west and south-west of Ireland.

Key Identification Features:

• Rosette-forming with blue-grey thallus and red discs (to 2mm diam.) with a grooved margin
• The species has neither isidia nor soredia; a kind of underfelt hypothallus is present.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Pannaria rubiginosa at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pannaria rubiginosa at iNaturalist World Species Observations database.