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Lecanora marginata (Schaerer) Hertel & Rambold
Family: Lecanoraceae
[Biatora elata (Schaer.) Hepp,  more]
Lecanora marginata image
Stephen Sharnoff  
Thallus: crustose, well developed, continuous or cracked-areolate, rarely dispersed, ecorticate; prothallus: prominent, white or bluish gray surface: lemon-yellow to yellowish white or rarely deep yellow, esorediate Apothecia: immersed initially, eventually becoming almost sessile, 0.5-1.5(-2.5) mm in diam. disc: black, flat to somewhat convex or even hemispherical, epruinose margin: black, persistent but soon becoming excluded, usually white pruinose, but typically obscured by the expanding disc, without a parathecial ring amphithecium: absent parathecium: externally black but internally hyaline except dark blue-green at outer edge (N+ red) epihymenium: yellow-green to dark blue-green or greenish black, N+ red hymenium: hyaline, 55-75 µm tall, paraphyses: 1.5-2.5 µm wide, simple or sparsely branched and anastomosed; apices: brown, swollen, capitate, 3.5-5(-6) µm wide; subhymeium: hyaline; hypothecium: hyaline, 80-200 µm thick asci: clavate, 8-spored ascospores: hyaline, simple, narrowly to broadly ellipsoid, (6.5-)9-14 x (4-)4.5-6(-7.5) µm Pycnidia: frequent conidia: vermiform to arc-like, 11-25 x 0.5-1 µm Spot tests: cortex K+ yellow, C-, KC+ yellow, P-; medulla P- or pale yellow, K- or K+ pale yellow, C-, KC-, P- Secondary metabolites: usnic acid and atranorin, both variable in concentration. Substrate and ecology: on hard, calcareous or base-rich rocks (sometimes weakly calciferous siliceous rocks), in exposed alpine or arctic sites World distribution: Holarctic-alpine of Europe, North America and Australia Sonoran distribution: Arizona. Notes: Lecanora marginata differs from L. oreinoides (Körb.) Zopf in having larger apothecia and a yellowish thallus containing usnic acid. In contrast, L. oreinodes differs in having a much more distinctly areolated thallus with aspicilioid sunken apothecia. Lecanora marginata differs from other lecideoid species in occurring on calcareous or base-rich rocks, having +pure black discs, and containing atranorin and usnic acids only. For example, Lecanora subimmersa (Fée) Vain. occurs on acidic substrates, has brown discs, and lacks usnic acid.
Lecanora marginata image
Stephen Sharnoff  
Lecanora marginata image
Stephen Sharnoff  
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image
Lecanora marginata image