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Physcia halei J. W. Thomson
Family: Physciaceae
Physcia halei image
Stephen Sharnoff  
Thallus: orbicular to irregular, up to 3 cm diam., loosely to firmly adnate lobes: up to 1 mm wide, margins mostly crenulate, eciliate upper surface: whitish gray to dark gray or cream-colored, with darker margins, mostly shiny and epruinose; without soredia or isidia upper cortex: paraplectenchymatous with rounded cells medulla: white lower cortex: paraplectenchymatous with rounded cells lower surface: white to brownish gray, often weakly rose colored Apothecia: common, up to 2 mm diam., usually around 1 mm; margins: crenulate; disc: dark brown to black, without pruina ascospores: brown, 1-septate, intermediate between Physcia- and Pachysporaria-types, (14-) 15-17 (-18.5) x (7.5-) 8-9.5 (-11) µm Pycnidia: usually numerous, immersed conidia: cylindrical, 3-4 x 1 µm Spot tests: upper cortex K+ yellow, C-, KC-, P+ yellow; medulla K-, C-, KC-, P- Secondary metabolite: upper cortex with atranorin. Substrate and ecology: seeming to prefer ± acid rocks in open situations World distribution: rather limited distribution in southern North America Sonoran distribution: a relatively common species at intermediate elevations in Arizona, Chihuahua and Sonora and less commonly in Baja California and Baja California Sur. Notes: Physcia halei is evidently the fertile counterpart of P. tribacia. It is in some modifications similar to P. cinerea but has a different chemistry lacking zeorin and additional triterpenes.
Physcia halei image
Stephen Sharnoff  
Physcia halei image
Stephen Sharnoff  
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image
Physcia halei image