Lecanora leptacinella Nyl.

in Norrlin, Not. Sällsk. Fauna Fl. Fenn. Förh., Ny Ser. ,13: 330, 1873.
Distribution: N - TAA (Nascimbene & al. 2021).
Description: Thallus crustose, episubstratic, consisting of more or less scattered, yellowish white, strongly convex, up to 0.5 mm wide areoles. Apothecia usually abundant, lecanorine, scattered to clustered, 0.3-0.7 mm across, broadly sessile or constricted at base, with an initially flat, then slightly convex, pale to dark brown or finally almost black disc, and a thin, smooth, often finally excluded thalline margin. Thalline exciple with relatively few algae, corticate, the cortex 50-75 µm wide in basal parts, consisting of more or less anticlinally oriented, thick-walled hyphae, often inspersed with crystals, I+ faintly blue; medullary part rather loose, inspersed with crystals; epithecium greenish brown, brown in upper part, K+ greenish, N+ purple, often with granules dissolving in K and reacting C+ red; hymenium colourless, 50-60 µm high; paraphyses branched, coherent, the apical cells capitate; hypothecium colourless, up to 70 µm high, 1+blue. Asci 8-spored, clavate, Lecidella-type. Ascospores 1-celled, hyaline, ellipsoid, 7-10 x 4-5 µm. Photobiont chlorococcoid. Spot tests: thallus and apothecial margin K+ yellow, C+ red, KC+ red, P-. Chemistry: alectorialic acid (major), plus traces of barbatic acid.
Note: an arctic-alpine species growing on moribund mosses (Polytrichum, Rhacomitrium, rarely other bryophytes) or on branches of subalpine shrubs (mostly Rhododendron); known from several stations in the Alps, but largely overlooked.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: very rare
Subalpine belt: rare
Oromediterranean belt: absent
Montane belt: absent
Submediterranean belt: absent
Padanian area: absent
Humid submediterranean belt: absent
Humid mediterranean belt: absent
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model

Curtis Randall Björk – CC BY-SA 4.0
Northwest Territories, near MacKay Lake Date: 2011-08-00 On moss in brushy tundra

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (13314)
white thallus with a single apothecium encrusting the leaflets of Polytrichum