Physcia phaea (Tuck.) J.W. Thomson

Beih. Nova Hedwigia, 7: 54, 1963. Basionym: Parmelia phaea Tuck. in Darlington - Flora Cestrica, ed. 3: 440, 1853.
Synonyms: Physcia aipolia subsp. phaea (Tuck.) Clauzade & Cl. Roux; Physcia melops Dufour ex Nyl.
Distribution: N - TAA, VA (Matteucci & al. 2015c).
Description: Thallus foliose, heteromerous, dorsiventral, narrow-lobed, closely adnate, forming orbicular to irregular, up to 5(-7) cm wide rosettes, several thalli sometimes merging to cover larger surfaces. Lobes up to 1-1.5(-2) mm wide, flat to convex, distinctly separated or more or less imbricate, the upper surface bluish grey to dark grey or brownish grey, usually strongly maculate owing to breaks in the photobiont layer, smooth more or less rugose; lower surface white to brownish, with white to black, scattered, simple rhizines. Upper cortex paraplectenchymatous; medulla white; lower cortex prosoplectenchymatous. Apothecia common, lecanorine, up to 1.5(-2) mm across, with a brown to black, sometimes white-pruinose disc and an initially crenulate, then smooth thalline margin. Epithecium brown; hymenium and hypothecium colourless; paraphyses slender, simple or forked in upper part, the apical cells clavate, with a thin, dark brown cap. Asci 8-spored, clavate, the K/I+ blue tholus penetrated by a faintly amyloid apical cushion with parallel or diverging flanks, the wall K/I-, surrounded by a K/I+ blue outer layer, Lecanora-type. Ascospores 1-septate, brown, ellipsoid, 15-21.5 x 6.5-11 µm, the wall thickened at apex and at septum, Physcia-type. Pycnidia black, usually abundant, immersed. Conidia subcylindrical, 4-6 x c. 1 µm. Photobiont chlorococcoid. Spot tests: upper cortex and medulla K+ yellow, C-, KC-, P- or P+ faintly yellow. Chemistry: upper cortex with atranorin; medulla with atranorin, zeorin and rarely other triterpenes.
Note: an arctic-alpine to boreal-montane, circumpolar lichen found on siliceous rocks slightly manured by birds, with optimum above treeline, up to the nival belt in the Alps. The record from Emilia by Valcuvia & Delucchi (2001), being dubious, is not accepted here.
Growth form: Foliose, narrow lobed
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

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
Herbarium samples
INDEX FUNGORUM GBIF DOLICHENS

Einar Timdal - Source: http://nhm2.uio.no/lav/web/index.html - CC BY-NC



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (28992)
2001/12/15



Felix Schumm – CC BY-SA 4.0
[5729], Canada, Ontario, Discovery Trail, Sharbot Lake Provincial Park, UTM Grid Reference: c364300 495900. Frontenac County. Easily removed from boulders. Leg. S.R. Olszewski, 08.08.1989 [No. 2493b], det S.R. Olszewski, 22.04.1990



Felix Schumm – CC BY-SA 4.0
[5729], Canada, Ontario, Discovery Trail, Sharbot Lake Provincial Park, UTM Grid Reference: c364300 495900. Frontenac County. Easily removed from boulders. Leg. S.R. Olszewski, 08.08.1989 [No. 2493b], det S.R. Olszewski, 22.04.1990



Felix Schumm – CC BY-SA 4.0
[5729], Canada, Ontario, Discovery Trail, Sharbot Lake Provincial Park, UTM Grid Reference: c364300 495900. Frontenac County. Easily removed from boulders. Leg. S.R. Olszewski, 08.08.1989 [No. 2493b], det S.R. Olszewski, 22.04.1990


Ulrich Kirschbaum CC BY-SA 4.0 - Source: https://www.thm.de/lse/ulrich-kirschbaum/flechtenbilder
Austria: Alps. (2700 m, on gneiss)


Wolfgang von Brackel - CC BY-4.0
Greenland, Narsarsuaq