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Peltula obscurans (Nyl.) Gyelnik
Family: Peltulaceae
[Acarospora subglebosa (Müll. Arg.) Hue,  more]
Peltula obscurans image
Stephen Sharnoff  
Thallus: squamulose, often widely scatted but in aggregate sometimes rosette-shaped squamules: lightly or deeply lobed, flat to convex, up to 2 mm diam. upper surface: olive-brown to brown, not sorediate upper cortex: not developed but with a yellowish epinecral layer (11-13 µm thick) medulla: consisting of loosely interwoven hyphae and partly paraplectenchymatous; algal layer: 90-180 µm thick lower cortex: usually present but not distinguishable from medulla lower surface: paler than the upper surface, attached by a branched umbilicus Apothecia: one per squamule (extremely rarely 2-3), adnate, with a raised rim when mature; disc: red to yellow-brown, 0.5-1 mm in diam.; epihymenium: yellowish brown, K+ red-violet; hymenium: I+ wine-red, 70-150 µm high asci: clavate to obclavate; wall: I+ orange but blue after pretreatment with K, >100-spored ascospores: ovoid to ellipsoid, 4.5-7.6 x 3 µm Pycnidia: immersed conidia: ovoid-fusiform, 3.1-3.7 x 1.2 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: usually on acidic rocks, occasionally calcareous one and soil in deserts and other open, arid habitats World distribution: southern Europe, South America, SW North America, Africa, Asia, Australia and Papua New Guinea Sonoran distribution: Arizona, California, Baja California, Baja California Sur, and Sonora.