Synonyms: Biatora hypopta (Ach.) Räsänen; Lecanora hypopta (Ach.) Vain.; Lecanora subintricata var. convexula Arnold
Distribution: N - TAA (Nascimbene & al. 2006e), Piem. C - Tosc (Benesperi & Lastrucci 2007, Giordani & al. 2009, Lastrucci & al. 2009), Abr (Stofer 2006), Sar (Zedda 2002). S - Cal (Nimis & Puntillo 2003, Puntillo 2011)
Description: hallus crustose, white to olivaceous grey, smooth to finely granulose or verrucose, sometimes poorly evident. Apothecia cryptolecanorine to biatorine, up to 0.6 mm across, broadly adnate, with a strongly convex, brown-black to black disc and a thin, soon excluded margin. Thalline exciple corticate, the cortex, especially in the basal part, with many black granules, the medulla without algae or with a few algae at the base only; epithecium bluish-green or reddish brown, without granules; hymenium colourless, 40-80 µm high, I+ blue; paraphyses coherent, the apical cells up to c. 4 µm wide; hypothecium colourless. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid to narrowly ellipsoid, 7-12(-16) x 3-6 µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on hard lignum, especially on decorticated stumps, more rarely on the bark of conifers in upland areas. According to Prinzen (in litt.), specimens identified as L. hypopta often belong to Lecanora hypoptoides or similar species (e.g. L. phaeostigma). The type of L. hypopta has a Pilocarpaceae/Porpidiaceae ascus and the species seeems to have a very special ecology, occuring on fallen tree trunks semi-immersed in lakes.