Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus very thin to lacking and within bark, whitish. Apothecia tiny, 0.2-0.4 mm, flat, black, sessile, with thin margin, becoming convex and immarginate; exciple brown or coppery brown; hypothecium hyaline; epihymenium brownish black; hymenium pale; paraphyses lax, tips capitate and brown; asci clavate; spores oblong to ellipsoid, both ends blunt, 3-septate, 10-16 X 3-4 µm. (Description after T. Fries and Tucker-man, I.e.)
This species is exceedingly rare, reported from Lapland on Populus, from Discovery Bay, Grin-nell Land, and Ellesmere Island on moss, and from the Reindeer Preserve, Mackenzie River area, on Populus.