Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus thin to dispersed or lacking, of tiny verrucules, ashy or ashy white. Apothecia 0.3-0.7 mm, broadly attached, black; disk flat; margin thin, black, more or less persistent; exciple reddish brown to reddish violet, reddish violet in K; the hyphae more or less radiate and thick-walled; hypothecium red to pale red-brown; epihymenium blue or bluish brown; hymenium 55-60 µm, upper part blue, 1+ blue; paraphyses lax, 1.5 µm, tips 4-5 µm; asci broadly clavate; spores 8-16 in ascus, straight or curved, oblong, tips rounded, 3-5-septate, 10-18 x 4-5 µm.
Reactions: exciple and hypothecium reddish violet in K, epihymenium turning violet with HN03.
This species grows on a variety of broadleaved plants, especially on Populus and Salix. It is known from Europe and North America, where it is eastern, from New England to Nebraska and Saskatchewan, but with one collection from Coppermine in the Northwest Territories.