Thompson, J., 1997. American Arctic Lichens: The Microlichens.
Thallus crustose, chinky-areolate, dull, areolae 0.3-0.4 mm, white. Apothecia large, 1.5-2 mm, sessile or raised; margin white, persistent; exciple nearly lacking cortex; disk convex or flat, black, eprui-nose; hypothecium hyaline, 1+ blue; epihymenium greenish brown, inspersed, HN03—, KOH— ; hymenium 1+ blue; paraphyses coherent, tips slightly clavate, to 2.5 μm; spores ellipsoid to narrowly oblong, 7-8 x 2.5-3 μm.
Reactions: K—, C —, P—, I—.
This species grows on calcareous rocks. It is rare, known only from Greenland and the arctic islands.
This species is similar to L. torrida, differing in having larger apothecia (1.5-2 mm vs 0.4-0.7 mm), and smaller spores (7-8 x 2.5-3 μm vs 8-11 x 4-5 μm).