ITALIC 8.0

Squamarina confusa Cl. Roux & Poumarat

Bull. Soc. linn. Provence, 75: 105, 2024.

Synonyms:

Distribution: N - Ven (Herb Nascimbene).

Description: Thallus squamulose, the squamules imbricate, white to pale green when fresh, more or less pruinose, irregularly lobed (but young thalli forming regular rosettes), the margins of marginal squamules sometimes white, the lower surface pale in young squamules, then black, attached by numerous, concolour rhizinoid hyphal strands. Upper cortex 30-85 µm thick, consisting of a 20-30 µm thick epinecral layer inspersed with crystals, and a 25-55 µm thick layer of mainly anticlinally arranged nyphae inspersed with crystals; medulla white (brownish in lower part), up to 0.5 mm thick. Apothecia frequent, lecanorine or weakly zeorine, 0.6-4.4 mm across, finally constricted at base, with a brownish, at first concave then flat to slightly convex disc, and a 0.1-0.35 mm thick, whitish, smooth, finally often excluded thalline margin, the proper margin thin and poorly evident, somehow glossy, level with disc. Thalline exciple 175-260 μm wide, corticate; proper exciple 105-180 μm wide, filled with crystals, the hyphae slightly arranged in a fan-way; epithecium yellowish brown, granular, 10-25 µm high; hymenium colourless, 60-90 µm high, hemiamyloid; paraphyses coherent, mostly simple, 1-1.5 μm thick at mid-level, the apical cells 2-4 μm wide; hypothecium colourless, 55-65 μm high, prosoplectenchymatous, the upper part with large crystals soluble in K and insoluble in N, I- (the subhymenium is devoid of crystals). Asci 8-spored, elongate-clavate, with a thin, outer amyloid layer and a thickened, amyloid tholus devoid of an ocular chamber, penetrated by an axial tube the sides of which stain I+ deeper blue, approaching the Porpidia-type. Ascospores 1-celled, hyaline, long-ellipsoid to subfusiform, (10-)12-16.5(-18.5) x (3.5-)4.5-5.5(-6.5) µm, with more or less pointed ends. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC- or KC+ faintly yellow, P-; medulla P+ yellow. Chemistry: cortex with usnic and isousnic acids; medulla with and 2ʹ-O-demethylpsoromic acids.

Note: a recently-described calcicolous species, easily confused with S. stella-petraea, probably more widespread in Italy, especially below the montane belt. For a more detailed description see Roux & Poumarat (2024).

Growth form: Squamulose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: extremely rare

Padanian area: absent

Humid submediterranean belt: extremely rare

Humid mediterranean belt: extremely rare

Dry mediterranean belt: extremely rare

pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model

Juri Nascimbene – CC BY-SA 4.0; Owner: Department of Life Sciences, University of Trieste

Feltre, Prov. Belluno, Veneto, Italy