Ahti, T., Jorgensen, P. M., Kristinsson, H., Moberg, R., Sochting, U., & Thor, G. (2007). Nordic Lichen Flora Vol. 3. Cyanolichens. Uddevalla: Nordic Lichen Society: 121.
THALLUS large, to 30 cm diam., lobes 3-4 cm wide, flexuous; margins ascending, crenulate; upper surface greyish green, wrinkled, tomentose also towards centre; cephalodia convex to cerebriform, to 1 mm wide; lower surface reticulately foveate with a broad, pale zone marginally, dark brown to black towards centre; rhizines separate bush-shaped, 1-3 mm long. APOTHECIA not uncommon, saddle-formed, disc to 10 mm diam., lower surface of apothecia with green corticate patches. Spores fusiform, 55-65 x 4-5 um CONDIDIOMATA unknown. PHOTOBIONT Coccomyxa, cephalodia containing Nostoc.
Chemistry. Tenuiorin, methyl gyrophate, gyrophoric acid, 2-5 unidentified hopane triterpenoids.
Habitat. On soil among mosses in riverine thickets, subalpine forests and low-alpine dwarf-shrub vegetation.
Distribution. Rare in central and northern Norway, Sweden and Finland but insufficiently known. F: OP PeP Ks KiL SoL EnL InL. N: Op ST OFi. S: Nb TL. Scandinavia, North America (Alaska), Siberia (Sakha), circumpolar, boreal to arctic.
Note: Resembles P. leucophlebia but is characterized by its tomentose thallus centre and reticulately foveate lower surface.