Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus ashy gray lo dark gray, forming very neat, small, orbicular patches, toward the margins with narrow lobes, 0.2-0.4 mm broad, dense and close together, convex and radiating, 3-5 mm long, the whole surrounded by a distinct black hypothallus; cortex 15-20 µm and transparent, of irregularly arranged cells. Apothecia to 1.5 mm broad, prominent to nearly sessile, single or 2-4 per central areola; thalloid margin K+ yellow; disk black, sometimes with thin pruina, flat or concave; hypothecium 1+ bluish; epihymenium dark olive, K+ more or less yellow; hymenium 80-100 µm, 1 + greenish yellow to reddish brown; paraphyses slender, 1 µm, upper cells 2-3 µm and submoniliform; spores 8, broadly ellipsoid or sub-globose, 13-18 x 8.5-11 µm. Conidia filiform, 16-22 x 0.5 µm.
Reactions: medulla K+ yellow.
Contents: not identified; norstictic acid appeared in traces in some MC tests.
This species grows on acid rocks in the open. It is circumpolar arctic, reported from Siberia, Novaya Zemlya, Spitsbergen, Greenland, the Northwest Territories, and Alaska.