Thallus: small, forming small squamules, rosettes or cushions squamules: fairly variable in size, 0.5-1.5(-2) mm wide, at first ±flat or convex, soon becoming crenate and lobulate at the margin, finally often irregularly concave with revolute margins or lobules ±ascending and thallus forming small cushions lobules: 100-150(-300) µm thick, heteromerous, centraly with thin, sometimes indistinct hyphal strand incorporating a few photobiont cells, (25-)50-100 µm thick, reticulate towards the lobe periphery, 50-100 µm thick upper surface: black, smooth except for the discs of the fruiting bodies lower surface: concolorous with the upper surface, dull, attached by tiny central umbilicus or tuft of rhizohyphae Apothecia: thallinocarpous, laminal to submarginal, 0.25-0.5 mm wide, immersed or semi-immersed, slightly convex, ±round, inconspicuous disc: rough, with a dotted texture; margin: thalline, up to 50 µm wide, indistinct; proper exciple: absent hymenium: hyaline, ±continuous, 100-150 µm tall, covered by wedge-shaped packtes of sterile thalline tissue up to 50 µm thick and intruding between groups of asci, IKI+ blue turning reddish brown or wine red; subhymenium: hyaline, continuous, 25-30 µm thick, IKI+ blue ascus: 24-32-spored ascospores: hyaline, simple, broad ellipsoid, small, 6-7.5 x 3-5 µm Pycnidia: globose to pyriform, sometimes compressed, (50-)100-125 µm wide conidia: ellipsoid, 2.5-3 x 1-1.5 µm Spot tests: all negative Secondary products: none detected. Substrate and ecology: on calcareous and siliceous rocks World distribution: North America Sonoran distribution: central Arizona, southern California, and Baja California Sur. Notes: Lichinella minnesotensis belongs to the squamulose members of the genus. It is distinguished from Lichinella intermedia and L. sinaica by the predominantly flat and adpressed squamules lacking ridged lobules.