Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus dark red-brown to dark brown, dispersed or contiguous areolate, the areolae to 2 mm broad, irregular, their surface verruculose, the verrucules often with pycnidia or apothecia. Apothecia with open disks, broad leca-norine margins; exciple hyaline, 15 μm; disk concave, reddish brown, 0.2-0.7 mm broad; hypothecium hyaline; hymenium 75-100 μm, 1+ yellowish to brown-red; paraphyses occasionally branched, slender, 2 μm; asci clavate; spores 8, hyaline, ellipsoid, sometimes with plasma bridge, 10-16 X 5-8 μm.
This species grows on slaty rocks and on soil, when on the latter being called f. terrigenum (Th. Fr.) Magnusson or Pyrenopsidium terrigenum (Th. Fr. in Hellbom) Forss. It is known from Scandinavia and from Greenland, where it was reported from God-havn by Gelting (1954) and from Julianehaab District by Dahl (1950). It is known from Melville Hills, Northwest Territories in the American Arctic.