Images of British Lichens
Degelia cyanoloma (Schaer.) H.H. Blom & L. Lindblom
Thallus blue-grey to lead grey, much paler brownish grey when dry, dark blue when wet, 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 (or poorly developed); apothecia usually present, red-brown to dark brown or blackish. A recently recognised Atlantic species, in Norway and in western Britain and Ireland, distribution uncertain but locally frequent in north-west Scotland, on mossy trunks and rocks, 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 developed isidia, and apothecia are common. It was previously considered a variant of D. plumbea but differs from that species in larger size, more prominent concentric ridges and usually darker apothecia. D. cyanoloma evidently replaces or largely replaces D. plumbea in north-west Scotland and many records for the latter species belong here.
|On Sycamore (Acer pseudoplatanus), Isle of Muck, June 2012 (BLS meeting)|
|In dry state, on Ash (Fraxinus excelsior), Ballygrant, Islay, May 2011 (BLS meeting)|
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Uploaded August 2011, last updated January 2016