Thallus 1-3 (-8) cm diam., irregular and appearing fragmented, sometimes coalescing with other thalli, ± firmly adnate, white to cream-coloured, sometimes appearing blueish due to dense development of soralia, ± shiny, the lobe tips sometimes darkening, very rarely pruinose. Lobes variously palmate and/or repeatedly branched, narrow, 1-2 mm in width, flat to slightly convex, not ciliate, slightly widening towards the apices, with well-developed concolorous isidia-like laminal outgrowths. Soralia sometimes abundant [not so in British material], lip-shaped on the edges of lateral lobes, also semicapitate and laminal, with farinose to ± granular, grey to blueish grey soredia. Lower surface corticate, pale to dark brown with a few scattered, short and robust, simple, mostly black rhizines. Anamorph: not known. Teleomorph: unknown in British material; ascomata apothecia, to 3 (-5) mm diam. with marginal sorediate lobules. Ascospores (28-) 31-37 (-43) x 12-17.5 (-28) µm, dark brown with a pigmented median septum, with very thick, uniform walls and rounded locules ('Pachysporaria' type). Chemistry: medulla C–, K+ yellow, KC± yellow, Pd– (atranorin and zeorin).