Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Epilithic thallus usually lacking, sometimes of isolated yellowish white, shining areolae to 1 mm broad; hypothallus lacking. Apothecia to 0.6 mm, usually less, shining black, epruinose, base narrow, at first flat and with obvious margin, becoming strongly convex and emarginate; exciple very clear as in Haplocarpon, the edge narrow, gray-green or dark green; hypothecium dark red-brown, turning red in K; epithecium gray-green to dark green; hymenium 35-55 μm, hyaline, strongly 1+ blue; paraphyses very conglutinate, partly branched and anastomosing, 2 μm, tips to 4 μm; spores ellipsoid, often apiculate, 9—18 x 5— 8 μm. Conidia short, 4-8 x 1.2 μm.
Reactions: medulla and lower apothe-cium K-, C -, KC -, P -, I - or + blue (weakly in the medulla).
This species grows on weakly calcareous rocks. Hitherto known from the Alps and Scandinavia, it was reported new to North America by Hertel (1981c) on the basis of a Scotter collection from the central Mackenzie Mountains, Northwest Territories.