This species has all the hallmarks of a member of the cyanobacteria-containing Pannariaceae in the shape of a usually well-developed blue-black edge (the hypothallus) to each colony. The central area consists of a pavement of cracked pale chestnut brown squamules so closely appressed as to suggest you are looking at a crustose not a squamulose lichen.
Photo: Ray Woods
Around the paler margins of each squamule coarsely granular cream-coloured soralia form. These can extend over most of the squamule surface. When covered in soralia this species can look like Parmeliella testacea. When fresh and moist this latter species can be easily detected by its strong antiseptic smell. Its soralia are also more blue-grey in colour, its marginal lobes more elongate and its hypothallus less well developed. (RGW)
Photo: Alan Orange