Slideshow image
Physcia magnussonii Frey
Family: Physciaceae
Physcia magnussonii image

Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: rock – siliceous, siliciferous, acidic | rock, stones, pebbles – unspecified.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: foliose (foliaceous), leaf-like; [th] upper surface: white(ish) | white(ish) grey | grey(ish) white; [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (median) 2.5 (max) 3.0; [th] morphol substructures (eg areoles, squamules): contiguous, coherent (throughout the thallus); [th] morphol substructures (eg areoles, lobes, branches) upper surface: smooth, plane.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma: sessile, superficial | subpedicellate, substipitate, subpedunculate, substalked; [ascm] paraphyses/-oids: present.  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: amyloid with widening axial body towards the apex (= Lecanora-, Parmelia-, Rinodina-types etc).  Ascospores: (median) 8.0; [asp] septa: present, transversely septate; [asp] transversal septa: (median) 1.0; [asp] pigmentation: medium brown, brownish; [asp] perispore, epispore: ornamented, rough, warted, striate, cracked.  Secondary metabolites: present, atranorin.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.