Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus dark olive-brown to dark brown, areolate, areolae flat to more commonly convex, dull or shiny, to 0.8 mm broad; black hypothallus often margining thallus. Apothecia sessile, raised above areolae, to 1 mm broad; proper exciple narrow but distinct, and with brown line below it limiting it from thalloid exciple; disk black, concave or flat, dull, bare; hypothecium dark cloudy. I — or 1+ blue; hymenium 100-150 µm, upper part yellowish olive, 1+ blue; paraphyses 2 µm, lacking septa and not moniliform, slightly branched (Magnusson (1939) noted that they were moniliform with the upper 3 or 4 cells globular, but Zahlbmckner (1928) described them as 1 have above); spores 8, ellipsoid, 9-17 x 6-9 µm. Conidia filiform, straight, 14-16 x 1 µm.
Reactions: K-, C—, KC-, I-.
This species grows on siliceous rocks. It appears to be circumpolar, known from Novaya Zcmlya, Scandinavia, U.S.S.R., Alaska, and the Northwest Territories, south to Washington and Saskatchewan.