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
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.