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Description

provided by The lichen genus Psora LifeDesk

Life Habit: lichenized, not lichenicolous; Thallus: squamulose, attached by the whole lower surface or basal end of squamule; squamules: dispersed, adjacent, imbricate, or ascending, 2-10 mm wide, rounded to elongate, with entire, crenulate or lobed margin, vegetative dispersal units lacking; upper surface: from grayish or greenish to dark brown, sometimes red or yellow, dull or shiny, epruinose to densely white pruinose, smooth to deeply fissured; upper cortex: varying from 35 to 200 μm thick, containing remnants of algae (chlor-zinc-iodine!), consisting of an upper epinecral layer and a lower stainable layer, the latter composed of thick- to rather thin-walled, anticlinally oriented hyphae with shortly thread-like, angular, or round lumina, often containing lichen substances and/or calcium oxalate; algal layer: 40-80 μm thick, horizontally continuous; photobiont: chlorococcoid, algal cells 10-15 μm diam.; medulla: white, of intricately interwoven hyphae, I-, often containing lichen substances and/or calcium oxalate; lower cortex: poorly to well developed, composed of periclinally or anticlinally oriented hyphae, sometimes containing calcium oxalate or anthraquinones; lower surface: white to brown; Ascomata: apothecial, laminal or marginal, sessile, with a constricted base, simple or rarely somewhat conglomerate, usually convex and immarginate but often plane and indistinctly marginate when young, up to 2 mm diam., brown to black, dull to shiny, epruinose or with yellow or white pruina; exciple: annular, continuous with upper cortex, colourless to pale brown, composed of thick-walled, strongly conglutinated, radiating hyphae; hypothecium: colourless to pale brown, composed of intricately interwoven hyphae densely inspersed by crystals of calcium oxalate and sometimes lichen substances, I-; epithecium: brown, containing brown cell wall pigments and orange crystals of anthraquinones (mainly parietin) (polarized light!), K+ red; hymenium: hyalin, I+ blue, 60-100 μm high; paraphyses: straight, sparingly branched and anastomosing, strongly conglutinated, apical cell slightly swollen; asci: clavate, with a well developed, amyloid tholus containing a deeper amyloid tube and lacking an ocular chamber (Porpidia-type), 8-spored; ascospores: colourless, simple, ellipsoid, smooth, without halo; Conidiomata: pycnidial, laminal, immersed, with colourless or pale brown ostiole, with short, sparingly branched conidiophores; conidia: acrogenous, bacilliform; Secondary metabolites: anthraquinones, depsides, depsidones, fatty acids, pulvinic acids, triterpens, and usnic acids.

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Diagnostic Description

provided by The lichen genus Psora LifeDesk

The genus is characterized by the squamulose thallus containing green, unicellular algae; lecideine apothecia; asci with amyloid tube in the tholus; simple, hyaline ascospores; presence of anthraquinones in the hymenium and calcium oxalate in the hypothecium; and immersed pycnidia with bacilliform pycnoconidia.

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Distribution

provided by The lichen genus Psora LifeDesk

Arctic to subtropical regions of the world, highest diversity in arid zones.

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Habitat

provided by The lichen genus Psora LifeDesk

Growing on soil and rock, often calciferous, in open habitats.

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Look Alikes

provided by The lichen genus Psora LifeDesk

Anamylopsora (no amyloid reaction in the tholus; no anthraquinones in the hymenium), Eremastrella (no anthraquinones in the hymenium), Glyphopeltis (no anthraquinones in the hymenium, no calcium oxalate in the hypothecium), Psorula (no anthraquinones in the hymenium, no calcium oxalate in the hypothecium, sessile pycnidia with ellipsoid pycnoconidia), Romjularia (no anthraquinones in the hymenium, no calcium oxalate in the hypothecium, sessile pycnidia with ellipsoid pycnoconidia).

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Timdal, Einar
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Timdal, Einar

Psora

provided by wikipedia EN

Psora is a genus of lichen-forming fungi in the family Psoraceae.[2] Members of the genus are commonly called fishscale lichens.[3][4] Lichens in the genus Psora are known to have a squamulose thallus and anthraquinones in the hymenium.[5]

Species

References

  1. ^ "Synonymy: Psora Hoffm., Deutschl. Fl., Zweiter Theil (Erlangen): 161 (1796) [1795]". Species Fungorum. Retrieved 11 November 2021.
  2. ^ Wijayawardene, Nalin; Hyde, Kevin; Al-Ani, Laith Khalil Tawfeeq; Somayeh, Dolatabadi; Stadler, Marc; Haelewaters, Danny; et al. (2020). "Outline of Fungi and fungus-like taxa". Mycosphere. 11: 1060–1456. doi:10.5943/mycosphere/11/1/8.
  3. ^ USDA Natural Resources Conservation Service Name Search
  4. ^ Fishscale Lichen (Psora), Encyclopedia of Life
  5. ^ Timdal, Einar (1984). "The delimitation of Psora (Lecideaceae) and related genera, with notes on some species". Nordic Journal of Botany. 4 (4): 525–540. doi:10.1111/j.1756-1051.1984.tb02059.x.
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Psora: Brief Summary

provided by wikipedia EN

Psora is a genus of lichen-forming fungi in the family Psoraceae. Members of the genus are commonly called fishscale lichens. Lichens in the genus Psora are known to have a squamulose thallus and anthraquinones in the hymenium.

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