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Pyrenula occidentalis (R. C. Harris) R. C. Harris
Family: Pyrenulaceae
[Pyrenula harrisii Hafellner & Kalb,  more]
Pyrenula occidentalis image
Stephen Sharnoff  
Thallus: continuous, superficial on the substrate upper surface: yellowish brown, smooth; pseudocyphellae absent photobiont: a trentepohlioid alga Perithecia: lenticular to hemispherical, black, semi-immersed in the thallus, c. 0.5-0.8 mm diam., K+ purplish in parts (but inside wall K-) ascomatal wall: black, continuous below the hamathecium hamathecium: composed of unbranched pseudoparaphyses, not anastomosing; filaments: c. 1 µm wide, not inspersed with oil droplets asci: cylindrical, with 8, irregularly arranged ascospores ascospores: medium brown, narrowly ellipsoid, 3-septate with distosepta leaving angular lumina, end cells with the lumina directly against the outer wall, 18-25 x 8-12 µm; walls: not ornamented, without a gelatinous sheath Pycnidia: often frequent, immersed conidia: colorless, ± hooked, 20 x 1 µm Spot tests: all negative or K+ yellowish, C-, KC-, P+ pale orange (of uncertain significance), UV+ yellow Secondary metabolite: lichexanthone. Substrate and ecology: on bark of various woody plants World distribution: north temperate Sonoran distribution: only recorded from southern California.