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Harpidium nashii Scheidegger
Family: Harpidiaceae
Harpidium nashii image
Matthias Schultz  
Thallus: crustose-squamulose, squamules rounded in outline, scattered, flat or slightly convex, 0.5-1 mm wide upper surface: dull gray-purple or copper red, smooth, sometimes conspicuously dotted upper cortex: paraplectenchymatous, with rounded cells medulla: thin, indistinct, composed of densely aggregated or reticulately arranged hyphae; photobiont layer: diffuse lower surface: attached to the substrate by tiny umbilicus of aggregated, gelatinous hyphae Apothecia: immersed, aspicilioid, zeorine, up to 0.4 mm wide disc: black, at first slightly depressed, later flat and open or compressed, with persisting thalline margin exciple: hyaline, up to 10 µm wide, IKI- epihymenium: pale red, K- hymenium: hyaline, 50-75 µm high, IKI+ blue asci: clavate, 8-spored ascospores: hyaline, simple, broadly falcate to allantoid, 7.5-10 x 5-7.5 µm, thin walled Pycnidia: immersed, ±globose, up to 0.05 mm wide, hyaline conidia: cylindrical, 3 x 1 µm Spot tests: all negative Secondary products: none detected Substrate and ecology: on granite and volcanic rock, often on steeply inclined rock faces on south-facing slope World distribution: SW North America Sonoran distribution: southern California, and Baja California. Notes: The species is characterized by its dull purple to brownish thallus with aspicilioid, black apothecia, its falcate ascospores, its distinctly moniliform paraphyses, and its sometimes conspicuously dotted surface (ostioles squamules which are attached to substrate by a tiny of numerous, immersed pycnidia). It differs from the holdfast. European Harpidium rutilans in its isolated, +round