Lecanora subravida Nyl.

Flora, 55: 250, 1872
Synonyms: Lecanora varia (Hoffm.) Ach. var. subravida (Nyl.) Nyl.
Description: Thallus crustose, fully endosubstratic or with scattered, up to 0.1 mm wide warts, up to 0.8 mm thick, yellowish brown-grey, matt, ecorticate, usually forming large patches. Apothecia lecanorine, 0.5-0.8 mm across, sessile and constricted at base, with a persistently flat, pale to medium brown, epruinose disc, and a distinct, smooth to finally knobby-crenulate thalline margin. Thalline exciple 160-190 µm wide, ecorticate in upper part, distinctly corticate in lower part, the cortex 40-80 µm wide, of anticlinally arranged, conglutinated hyphae, the medullary part filled with granules: proper exciple not developed; epithecium pale brown, with small yellowish granules, N-; hymenium colourless, without granules, 50-65 µm high; paraphyses simple to rarely sparingly branched, 1.5-2 µm thick at mid-level; hypothecium colourless, 50-70 µm high. 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, broadly ellipsoid, 9.4-11 x 5-6.2 µm. Macropycnidia rare, 120-140 µm across, producing falcate macroconidia measuring 12.5-13 x 2.8-3 µm; micropycnidia very rare, 50-70 µm across, producing curved microconidia measuring 7-8 x c. 0.8 µm; leptopycnidia abundant, globose, c. 90 µm across, producing curved leptoconidia measuring c. 1 x 0.8 µm. Photobiont chlorococcoid. Spot tests: K+ yellow or K-, C-, KC+ yellow, P-. Chemistry: usnic and placodiolic acids (major/minor), plus variable amounts of isousnic and squamatic acids.
Note: on wood, or on the bark of old trunks of conifers, with several scattered, mostly ancient records in the Alps, all outside Italian territory; to be looked for in the Italian Alps.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

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