A distinctive, rosette-forming species with a bluish grey to green-brown thallus that consists of imbricate squamules or radiating lobes that are much incised and have a distinctly paler margin. The lobes may be slightly pruinose. The grey to black, hairy prothallus is usually visible at the edges of the thallus. The chestnut-red apothecia often have a crenulate margin.
In Scotland, Pannaria rubiginosa occurs mainly in the central and western Highlands where it usually overgrows damp mosses on broadleaved trees and rocks in damp, sheltered woodland. BLS distribution map
Pannaria rubiginosa is distinguished from Pannaria conoplea by the absence of any isidia.
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