Thompson, J. 1984. American Arctic Lichens: The Macrolichens.

Thallus caespitose in small rosettes to 15 mm broad, the lobes erect, branching, to 0.8 mm tall, attached by tufts of rhizinae, verruculose, blackish brown, lacking cortex, the medulla with a loose network of hyphae forming broad lacunae, the Nostoc in chains and distributed through the thallus. Apothecia black, rarely brown, to 1.0 mm broad, the proper margin indistinct; subhymenium hyaline or brownish, 110-170 μ; hymenium 120-190 μ, upper part brown; paraphyses filiform, 1-1.5 μ, lax, gelatin abundant; asci subclavate, 85-115 x 12.5-17.5 μ; spores 8, hyaline, simple, globose to ovoid, 16-23 x 11-14 μ.

This species grows on mosses and other lichens over limestone soils in moist habitats. It is known from Scandinavia, Novaya Zemlya, Iceland, Greenland, and in North America from Ellesmere Island to Alaska.