Thallus squamulose. Squamules to 3 mm diam., scattered to contiguous, sometimes irregularly imbricate, rounded or irregularly lobed, weakly convex to swollen. Upper surface dull olive-green to brown, usually ± densely white- or blue pruinose, dull to slightly shiny, sometimes appearing greasy, smooth or sometimes with shallow fissures in the cortex, without pseudocyphellae. Margin concolorous with upper side or often more densely white, farinose-pruinose. Underside white to pale brown. Upper cortex 20-60 μm thick, including a 20 μm thick epinecral layer, often containing (or overlain by) calcium oxalate crystals. Lower cortex resembling the upper, but thinner and lacking crystals. Medulla without crystals. Photobiont zone continuous, containing chlorococcoid algae. Anamorph: not known. Teleomorph: ascomata apothecia, to 3 mm diam., weakly concave to weakly convex, not to densely farinose and white-pruinose.
True exciple raised when young, often later becoming excluded, medium to dark brown throughout, K– and N–, or K+ violet and N+ violet (additional grey pigment). Epithecium grey, often containing crystals of calcium oxalate, K+ violet, N+ violet. Hymenium 70-80 μm tall, hyaline. Hypothecium medium brown in lower part, dark brown in upper part. Interascal tissue of paraphyses, straight, simple or sparingly branched and anastomosed, not conglutinated, thin-walled, the apical cell distinctly swollen and covered by a ± well-developed, gelatinous pigment cap. Asci clavate, surrounded by a gelatinous, K/I+ blue sheath, with a well-developed, K/I+ blue tholus containing a deeper-staining tube and pronounced ocular chamber, Bacidia-type, 8-spored. Ascospores 14-25 × 2.5-5 μm, fusiform, 1-septate, hyaline, thin-walled, smooth, without an epispore, gelatinous sheath or appendages. Chemistry: lichen products not detected by TLC or with traces of fatty acids or unidentified substances.