Physcia magnussonii Frey

Erg. wiss. Unters. Schweiz. Nationalpark Unterengadin, n. F. 3, 27: 480, 1952.
Synonyms: Physcia aipolia var. subincisa (Th. Fr.) Lynge; Physcia stellaris var. subincisa Th. Fr.
Distribution: N - TAA, Lomb (Favero-Longo & al. 2023), Piem (TSB 34161), VA (Piervittori & Isocrono 1997, 1999, Piervittori & al. 2001, Isocrono & al. 2008), Emil (Fariselli & al. 2020). C - Tosc (Giordani & al. 2009).
Description: Thallus foliose, heteromerous, dorsiventral, narrow-lobed, closely adpressed, forming orbicular, up to 8 cm wide rosettes. Lobes to 3 mm wide, usually overlapping, more or less convex, whitish grey to brownish grey, emaculate, distinctly and densely white-pruinose. Lower surface white to brownish, with a few, stout, simple rhizines. Upper cortex paraplectenchymatous; medulla white. Apothecia common, lecanorine, to 3 mm across, with a usually white-pruinose, otherwise black disc and a smooth thalline margin. 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 K/I+ blue outer layer, Lecanora-type. Ascospores: 1-septate, brown, narrowly ellipsoid, 16-24 x 6-9 µm, the wall with a distinct verrucose ornamentation, thickened at apex and at septum, Physcia-type. Pycnidia common, immersed, black. Conidia subcylindrical. Photobiont chlorococcoid. Spot tests: cortex K+ yellow, C-, KC-, P+ yellow; medulla K- or K+ pale pink, C-, KC-, P-. Chemistry: cortex with atranorin.
Note: on steeply inclined surfaces of base-rich siliceous rocks, often starting its development in fissures of the rock; for Italy hitherto known only from the Alps and the northern Apennines, but is likely to be found on some Mediterranean mountains with suitable substrata.
Growth form: Foliose, narrow lobed
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
On otherwise dry surfaces with short periods of water seepage after rain

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: rare
Oromediterranean belt: absent
Montane belt: very rare
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


P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (20316)
2001/12/11