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Epilichen stellatus Triebel
Family: Rhizocarpaceae
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Mycelium: within the host thallus, inconspicuous, nonlichenized Ascomata: black, urceolate, breaking through the surface of areolae or apothecia of the host lichen, with plane discs and distinct margins but margin occasionally EPILICHEN exciple: externally carbonaceous, blackish brown, internally brown to pale, hymenium: hyaline, 60-65 µm tall paraphyses: branching and anastomosing, 1.5-2 µm wide below, with tips enlarged up to hypothecium: brown, 50-60 µm thick asci: subventricose to clavate, 45-60 x 11-15 µm, 8-spored ascospores: greenish brown when young, later dark brown, 1-septate, ellipsoid, somewhat attenuated at both ends and slightly constricted at the septum, 10-14 x 5-6.5 µm; wall: thick, distinctly layered Conidiomata: not observed. Host: known only from Lecidea tessellata; on the thallus and apothecia, parasitic, but not visually damaging the host World distribution: rare in northern Asia, relatively common in North America (Canada, U.S.A., and Mexico) Sonoran distribution: throughout Arizona. Notes: The species was originally described on the basis of a single specimen from northern Siberia but has turned out to be widely distributed in North America (Triebel et al. 1991).