Degelia cyanoloma (images of British lichens)

Thallus blue-grey to lead grey, much paler brownish grey when dry, marked above with longitudinal marks and striations and with lobes concentrically undulate-ridged, giving the thallus a shell-like appearance, felted blue-black beneath and at the margins, isidia absent; apothecia usually present, dark red-brown to blackish. A recently recognised Atlantic species of western Britain and Ireland, distribution uncertain but locally frequent in north-west Scotland, on mossy trunks and rocks, evidently a characteristic species of the 'Celtic Rainforest'.

Refs: Blom & Lindblom (2009), Lichenologist 42: 23-27; Dobson (2011), 167 (photo); Whelan (2011), 90 (photo).

Closely resembles D. atlantica but lacks isidia, and apothecia are common; previously considered a variant of D. plumbea but differs from that species in larger size, more prominent concentric ridges and darker apothecia.

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Images of British Lichens