Rinodina gennarii Bagl.Thallus crustose, thinly episubstratic, rimose to rimose-areolate, sometimes reduced to a few small areoles around the apothecia, whitish to dark grey or grey-brown, dull, rarely delimited by a dark prothallus. Apothecia lecanorine, abundant and usually crowded, adnate, 0.3-0.5(-0.7) mm across, with a dark brown to almost black, epruinose, flat to markedly convex disc and a thin, smooth, finally sometimes excluded thalline margin. Thalline exciple 20-100 µm wide laterally, expsnding in lower part, the cortex 5-10 µm thick; proper exciple 5-20 µm wide laterally, expanded to 20-30(-55) µm at periphery; epithecium dark brown, 5-15 µm high, K-; hymenium colourless, 60-80(-90) µm high, K/I+ blue; paraphyses 1.5-2.5 µm thick at mid-level, not very coherent, the apical cells 3-6 µm wide; hypothecium colourless, up to 150 µm high. Asci 8-spored, narrowly clavate to clavate, the K/I+ blue tholus penetrated by a faintly amyloid apical cushion with parallel or diverging flanks, the wall K/I-, surrounded by a K/I+ blue outer layer, <i>Lecanora</i>-type. Ascospores 1-septate, brown, broadly ellipsoid, sometimes slightly curved, (11-)13-16(-18) x (6-)7-10(-11) µm, <i>Dirinaria</i>-type, not thickened at apex and slightly swollen at septum in K, the torus absent, the ontogeny of type B (apical thickenings visible before the insertion of the septum). Pycnidia immersed in thallus, black, pyriform. Conidia bacilliform, 4-6 x c. 1 µm. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances. 