Ahti, T., Jorgensen, P. M., Kristinsson, H., Moberg, R., Sochting, U., & Thor, G. (2007). Nordic Lichen Flora Vol. 3. Cyanolichens. Uddevalla: Nordic Lichen Society: 122.
THALLUS to 10 cm diam., thickish, lobes 0.5-1 cm wide; margins plane to elevated; upper surface scabrous, greyish green to browned; lower surface veinless, blackened towards the centre, with small white spots; rhizines few, fasciculate, 1-2 mm long, thick, diffuse or scattered. APOTHECIA very rare (only immature ones seen), disc convex. Spores not seen. CONIDIOMATA unknown. PHOTOBIONTNostoc.
Chemistry.Tenuiorin, methyl gyrophorate, gyrophoric acid, peltidactylin, dolichorrhizin, hopane-7B,22-diol and hopane-15a,22-diol.
Habitat. On soil among mosses.
Distribution. Very rare, arctic. I: IMi. AI: Sb. Europe, Asia, North America; probably circumarctic.
Note. Poorly known (or overlooked) species; its non-veined lower surface with sparse, subsimple and short rhizines characterizes it against P. scabrosa. Careful observations in the field are needed to elucidate the relationships of these two species.