Rhizoplaca subdiscrepans (Nyl.) R. Sant.

The Lichens of Sweden and Norway: 278, 1984. Basionym: Squamaria chrysoleuca var. subdiscrepans Nyl. - Flora, 44: 718, 1861.
Synonyms: Lecanora subdiscrepans (Nyl.) Stizenb.; Squamaria chrysoleuca var. lecanorea Anzi?
Distribution: N - Lomb (Ravera & al. 2022b).
Description: Thallus crustose-subsquamulose, pale yellowish green to whitish-green, to c. 3 cm across, of scattered to crowded, 0.3-1.3 mm wide, convex-bullate, sinuous and plicate areoles attached by a narrowed base, the marginal ones often slightly elongated and c. 1-1.5 mm long. Upper cortex of strongly gelatinized hyphae, often heavily inspersed with crystals, the cell walls with isolichenan; medulla white, loose. Apothecia lecanorine, 0.7-2(-3) mm across, sessile and constricted at base, with a slightly concave to flat, pale pink to orange, pruinose disc, and a 0.1-0.2 mm wide, entire to flexuose, somewhat raised and slightly inflexed, usually persistent thalline margin. Proper exciple colourless, cupulate; epithecium orange-brown, covered with granules; hymenium pale yellowish, not inspersed with oil droplets; paraphyses scarcely thickened to capitate, 3-5 µm wide at apex. Asci 8-spored, clavate, the tholus with a strongly amyloid lateral part, a non-amyloid broadly diverging axial mass with a thick, non-amyloid cap above, and a weakly amyloid outer layer Lecanora-type. Ascospores 1-celled, hyaline, oblong, 8.5-13.5 x 3.5-4.5(-6) μm. Pycnidia black, immersed. Conidia thread-like, 15-25 µm long Photobiont chlorococcoid. Spot tests: cortex: K- or K+ yellow, C-, KC+ yellow, P-, UV-; medulla: K-, C- or rarely C+ red, KC- or rarely KC+ red, P-, or P+ yellow, UV-. Chemistry: upper cortex with usnic acid and variable amounts of either placodiolic or pseudoplacodiolic acid; medulla with aliphatic acids or no substances, or, occasionally with psoromic and/or lecanoric acids.
Note: on the top of calciferous or basic siliceous boulders frequently visited by birds, with optimum above treeline.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Poorly known taxon in need of further study

Commonnes-rarity: (info)

Alpine belt: very rare
Subalpine belt: extremely 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:

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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


P.L. Nimis CC BY-SA 04
TSB 43979



Curtis Randall Björk – CC BY-SA 4.0
British Columbia, Clearwater Valley, Hemp Creek Canyonlands Date: 2011-06-01 On basalt boulder in open, dry forest



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (25985)
2001/12/01



Pier Luigi Nimis - CC BY-SA 4.0
TSB 43979