Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus crustose, variable from thick and uneven to verrucose, of scattered verrucae, or disappearing, grayish white to brownish gray. Apothecia to 1.5 or 2 mm broad, sessile; margin thin, entire to crenulate or flexuous, cortex 1+ blue; disk black or brownish black, flat or concave, bare; hypothecium hyaline; epihymenium brownish; hymenium 110-115 μm, hyaline, 1+ blue; paraphyses 1.5-2 μm, tips to 3-3.5 μm and with a brown cap; asci broadly clavate; spores dark olive or olive-brown, apical walls convex inward, septum distinct, porus distinct, 26-35 x 11-14 μm.
Reactions: thallus K—, C . P—.
This species grows on moss, decaying vegetation, rotting lichens, and rotting wood. It is a common circumpolar arctic-alpine lichen, ranging in North America south to California, Alberta, and Saskatchewan.