Hypothallus endosubstratal, IKI−. Thallus contiguous, indeterminate, of small broadly attached areoles becoming subsquamulose or squamulose, (0.5–)1–2 mm wide, stipe or mycelial base up to 0.2 mm high, underside white. Upper surface creamy yellow brown, usually smooth, rarely fissured, epruinose to lightly pruinose, edges downturned. Epicortex 50 μm thick when growing in full sun. Cortex 60–100 μm thick, cells mostly round, 3–5 μm wide. Algal layer even, 100–200 μm thick, algal cells 10–20 μm wide. Medulla 200–400 μm thick, obscure with crystals, hyphae continuous with mycelial base or stipe. Apothecia 1 per squamule or areole, usually 1 mm wide, rugulose with cortical remnants forming an umbo or ridges of epihymenial plectenchyma on the disc surface. Parathecium expanding around apothecial disc up to 60 μm, often visible as parathecial ring of the same color as the thallus, hyphae ca. 1 μm wide. Hymenium 150–170 μm high, epihymenium light reddish brown, usually 10 μm high, color sometimes extending downward as much as 40 μm into hymenium, paraphyses usually 2 μm wide, apices expanding to 3 μm, hymenial gel IKI+ euamyloid. Asci 90–150 × 17–35 μm wide, ascospores mostly 4–5 × 2 μm. Subhymenium IKI+ blue, ca. 30 μm high. Hypothecium ca. 20 μm thick. Pycnidia with conidia 1.0 × 0.5 μm.
Secondary metabolites: gyrophoric acid in cortex.
Ecology and substrate: on siliceous rock in arid hills. World Distribution: Chihuahuan Desert, New Mexico.