Thallus: continuous, smooth, immersed in the substrate, not well delimited upper surface: whitish gray, smooth photobiont: absent or associated with Trentepohlia Perithecia: hemispherical, black, circular, scattered singly, semi-immersed in the thallus, 0.1-0.2 mm diam. involucrellum: greenish brown, composed of leptodermatous cells; true ascomatal wall: black, absent below the hamathecium exciple: colorless to dark brown, continuing below the hymenium; hymenium I+ bluish hamathecium: mostly unbranched pseudoparaphyses, not anastomosing; filaments: c. 2 micrometer wide, not inspersed with oil droplets asci: pyriform, c. 40-55 x 10-28 micrometer, with 8, irregularly arranged ascospores ascospores: hyaline, fusiform to bacilliform, curved, sometimes sigmoid, 1-3 septate with a median euseptum, 24-28 x 2.5-3.5 micrometer; walls: not ornamented, without a gelatinous sheath Pycnidia: black Spot tests: all negative, UV negative Secondary metabolites: none detected. Substrate and ecology: on bark of Populus World distribution: temperate in Northern Hemisphere Sonoran distribution: only collected in southern Arizona. Notes: The specimen had been incorrectly identified as the related Leptorhaphis epidermidis (Ach.) Th. Fr., which differs by its ellipsoid ascomata and its different host preference (Betula instead of Populus).