Lecanoraceae Protoparmeliopsis muralis (Lecanora muralis) Growth type crustose, placodioid. Chemical results: K-, C-, P- or P+ yellowish Very common in urban areas on roof-tiles, concrete, asphalt, pavements and walls. Also found on nutrient-rich bird-perching rocks. The pale greenish-grey to yellow-grey lobular thallus has clearly lobed outer margins. Numerous apothecia with brown or creamy-brown discs, their margins +/- crenulate when mature. Similar: Lecanora pruinosa, C+ orange, UV+ orange

Lecanora muralis
Dorset. March 2012, February and April 2013