Thallus indeterminate, squamulose-areolate, +/- pale dark brown/grayish-brown-red, areolae subcontiguous or dispersed, somewhat thick, convex and very unequal, tuberculate, shiny, base constricted, +/- loosely affixed, pale below, KOH-, CaCl-. Apothecia solitary or a few, immersed, often rare, disc concave, black, irregular, scabrous, surrounded by indistinct margin. Upper cortex moderate, covered by thick, amorphous layer. Medullar hyphae lax. Hymenium somewhat thick, spores very thin, ellipsoid.
Areolae 1-2.5 mm large, 0.5-1 (1.5) mm thick, rarely contiguous for 1-2 cm, mostly grouped and separated by unequally broad cracks, or +/- isolated, of an unusual, rather pale brown-red colour, mostly very shiny, apparently subpellucid, often thinly white marginated from the thick amorphous stratum. Surface unevenly and densely tuberculate (Fig. 2).
hyphae 3-3.5 µ thick, moderately thick-walled, with ± abundant, angular crystals on their surface, in HCl lax to very lax, loosely intricate with cylindric lumina. Lower surface widely
attached, pale.
Apothecia rare in most parts of the thallus, sometimes crowded in a small area, very irregular in shape and size, disc0.3-0.5 (0.6) mm broad, ± deeply concave, almost smooth or usually somewhat rough or even rugose, not always distinctly limited towards the slightly prominent thallus margin.
Wetted apothecia 0.7-1 mm broad, 150-300 µ deep at the centre, only 50-70 (100) µat the margins. Exciple very thin below, 50-70 µ at the surface. Hypothecium 50-100 µ
thick, I+ dark blue. Hymenium(85) 90-110 µ high, lower limit indistinct; I+ dark or pale blue. Paraphyses 1.7 (2) µ thick, dense, apices in KOH red-brown capitate, 4-5 µ, discrete, with ± thick amorphous stratum. Asci65-85 x 20-25 µ. Spores100-200, in KOH 3-3.5 x 2--2.5 µ, broadly ellipsoid to subglobose.
Pycnoconidia 1.7 (2) x 0.7 µ upon about 10 µlong sterigmata.
Habitat.On granitic stone with Caloplaca elegansetc., indicating a place rich in ammonium salts.
Locality.West Greenland. Nugssuaq Peninsula north of Disko: Atanikerdluk, 1881, Th. Fries, several specimens.