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Physcia phaea (Tuck.) J. W. Thomson
Family: Physciaceae
[Parmelia phaea Tuck.]
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Stephen Sharnoff  
Thallus: orbicular to irregular, up to 3 cm in diam. or more when confluent with other thalli, lobes ± imbricate lobes: up to 1.5 mm wide but usually around 1 mm, flat or slightly convex, particularly at tips, eciliate upper surface: gray to dark gray or brownish gray, usually strongly maculate and ± rugose; soredia and isidia lacking upper cortex: paraplectenchymatous medulla: white lower cortex: prosoplectenchymatous lower surface: white to brownish, with white to black, scattered rhizines Apothecia: numerous, up to 1.5 mm across, usually smaller; margin: crenulated when young; disc: brown to black, sometimes covered with a white pruina ascospores: brown, 1-septate, Physcia-type, (15-) 16.5-20 (-21.5) x (6.5-) 7-9.5 (-11) µm Pycnidia: numerous, immersed conidia: subcylindrical, 4-6 x 1 µm Spot tests: upper cortex and medulla K+ yellow, C-, KC-, P+ yellow Secondary metabolites: upper cortex with atranorin; medulla with atranorin, zeorin and occasionally some other triterpenes. Substrate and ecology: growing on rocks in open situations World distribution: known from more northern parts of North America and from Europe Sonoran distribution: a relatively frequent species from coastal regions to upper montane areas in Arizona, southern California, Baja California, Baja California Sur, Chihuahua, Sonora and Sinaloa. Notes: Physcia phaea is easily recognized by the strong maculation and the rugose upper surface, the abundant apothecia and by the chemistry. The K reaction in the medulla is not a good diagnostic character (see P. nashii and P. neglecta).
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Stephen Sharnoff  
Physcia phaea image
Stephen Sharnoff  
Physcia phaea image
Stephen Sharnoff  
Physcia phaea image
Stephen Sharnoff  
Physcia phaea image
Stephen Sharnoff  
Physcia phaea image
Stephen Sharnoff  
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
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Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Physcia phaea image
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Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Physcia phaea image
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Physcia phaea image
Physcia phaea image
Andrew Khitsun  
Physcia phaea image
Andrew Khitsun  
Physcia phaea image