''Degelia plumbea'' (also called blue felt lichen) is a species of grey to blue-black or brown foliose

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Degelia ''Degelia'' is a genus of lichen-forming fungi in the family Pannariaceae. The genus is named after Swedish lichenologist Gunnar Degelius. The genus was circumscribed by Lars Arvidsson and David John Galloway in 1981. Species *''Degelia calc ...

''. It mostly grows on trees in undisturbed woodlands but occasionally on coastal rocks. It is found widely in Britain and western Ireland as well as in America and Canada, as it grows in

maritime Maritime may refer to: Geography * Maritime Alps, a mountain range in the southwestern part of the Alps * Maritime Region, a region in Togo * Maritime Southeast Asia * The Maritimes, the Canadian provinces of Nova Scotia, New Brunswick, and Princ ...

Atlantic climates. ''D. plumbea'' is highly sensitive to

acid rain Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid ...

and climatic changes. '' Degelia cyanoloma'' was previously thought to be a variant of ''D. plumbea''.

References

Peltigerales Lichen species Lichens described in 1777 Lichens of Europe Lichens of North America Lichens of Eastern Canada {{Peltigerales-stub