E-Flora BC: Electronic Atlas of the Flora of British Columbia

Physconia perisidiosa (Erichsen) Moberg
Smirking frost

Introduction to the Lichens
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E-Flora BC Static Map
Distribution of Physconia perisidiosa
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Consortium of North American Lichen Herbaria map

Species Information

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Illustration By: Trevor Goward

Common Name: The Frost Lichens. Alludes to the characteristic presence of white pruina over the upper surface of the species.
Medium stratified foliose lichens, corticate above and below (ours), sorediate or isidiate or not, lobes appressed to loosely attached, elongate, averaging to 0.5–2 (–3) mm wide, thin. Upper surface brownish, except often heavily white-pruinose, K-, dull to somewhat shiny. Lower surface pale to more often blackish, dull, bearing numerous squarrose rhizines. Medulla white or occasionally pale yellow. Photobiont green.
Apothecia located over upper surface, disc white-pruinose; spores 2-celled, ellipsoid, brown, 8 per ascus.
Over calcium-rich substrates, including rock, soil, duff, bark and bone.
Notes: Seven species of Physconia are reported for North America and five of these are known to occur in B.C. Chemistry is of little taxonomic importance in this genus, with the exception of the K+ yellow medullary reaction of P. enteroxantha. See, however, the notes under that species. The species currently assigned to Physconia were formerly treated within Physcia. The genus is under taxonomic review by T. Esslinger; this treatment is provisional.
Species description:
Thallus bearing soredia and/or isidia (check lobe tips) AND
Soredia/isidia mostly confined to lower surface, especially at lobe tips; lobe tips upturned; lower surface pale, darkening only gradually toward thallus centre
All spot tests negative.
No lichen substances reported.

Source: Lichens of British Columbia

Habitat / Range

Habitat: Infrequent over deciduous trees, shrubs and (mossy) base-rich rocks at lower elevations in open maritime and intermontane sites;
World Distribution: probably incompletely circumpolar, N to BC, S to CO.

Source: Lichens of British Columbia

Synonyms and Alternate Names

Physconia farrea

Taxonomic and Nomenclatural Links

Additional Range and Status Information Links

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General References