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Leptogium papillosum (B. de Lesd.) Dodge
Family: Collemataceae
Leptogium papillosum image
Thallus: foliose, 3-10(-15) cm in diam., loosely adnate, subdichotomously to irregularly lobate lobes: irregular, flabellate, +plane, separate, 3-15(-20) mm wide, 120-150 µm thick; apices rotund, entire to crenate and isidiate, occasionally upturned upper surface: medium gray to bluish gray, dull to somewhat shiny, with distinct wrinkles, isidiate to sometimes phyllidiate isidia: scattered to dense, usually laminal but sometimes marginal, usually semi-globular to clavate, often with wrinkles when dry, simple or irregularly branched, concolorous with the thallus or more often darker internal anatomy: with upper and lower cortices consisting of a single layer of irregularly isodiametrical cells, internally with loosely interwoven chains of Nostoc and hyphae lower surface: pale to medium gray, smooth, with dense white tomentum of cylindrical hairs up to 0.2 mm long Apothecia: frequent, laminal, stipitate, 2-4 mm wide disc: brown to red-brown, plane to convex margin: thalline, concolorous with the thallus, isidiate, often pubescent exciple: euparaplectenchymatous, 20-25 µm centrally hymenium: hyaline below and thinly brown above, 100-125 µm tall; paraphyses: unbranched, 1-2 µm wide, slightly inflated apically; subhymenium: pale yellow, 20-25 µm thick asci: cylindrico-clavate, 8-spored ascospores: hyaline, submuriform, 3-4-septate transversely, 0-1-septate longitudinally, ellipsoid with acuminate ends, 25-35 x 10-12 µm Pycnidia: not observed Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on bark World distribution: North and South America Sonoran distribution: Arizona. Notes: Because it is isidiate with extensive tomentum on lower surface, Leptogium papillosum has been confused with L. pseudofurfuraceum, which is a smaller, thicker, much browner species with different spores.