Thallus white or blue-gray, usually with a pale hypothallus, verrucose to squamulose with convex upper surfaces. Apothecia numerous, dispersed or loosely grouped, closely adnate, 1-1.5 mm broad; margin thick, prominent in some specimens, in others the proper exciple is thin and separate from the thalloid margin, which becomes thick, crenulate, and reflexed; the apothecial cortex is of paraplectenchymatous hyphae bordered by a thin anticlinal layer which may appear spinulose, the outer layers inspersed with a violet-gray amorphous substance; disk dark brown, rough, flat; hymenium 70-80 µm; paraphyses clavate to capitate, tips to 6 µm and covered with a violet-gray substance; spores 8, often poorly developed, 12-18 X 6.5-8 µm, septum 2-3.5 µm.

This species is found on calcareous rocks, basalts, and gneisses, growing in seepage areas. It was described from Europe and the Mediterranean region, reported from Disko Island and Christians-haab regions in Greenland. Anderson (1967) reported it from Colorado, so that it should occur in the American Arctic, although no records are yet known.

Thallus reticulate chinky, ashy to brownish ashy. Apothecia adnate, 0.4-0.7 mm broad; margin of same color as thallus, subparaplecten-chymous; disk black to brownish black, epruinose, flat to becoming convex; hypothecium hyaline; epihymenium brownish; hymenium 80-90 μm, hyaline, 1+ blue; spores 2-celled, hyaline, sometimes few with septation, ellipsoid, 13-17 X 7-9 μm.

This species grows on noncalcareous rocks. It is known from Novaya Zemlya and from Devon Island, Southampton Island, and the Melville Hills in the Northwest Territories.

On examination of the type specimen of this species from Novaya Zemlya, M. Mayrhofer (1988) places it as Caloplaca diphyodes (Nyl.) Jatta.

Note: The current name K. diphyodes applies to European, not Arctic-alpine specimens. Arctic-alpine material of Caloplaca diphyodes is shown to be not related to the type material, collected in France, and instead belongs in Pyrenodesmia s. str. See note in P. helygeoides.