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Rostania occultata (Bagl.) Otálora, P. M. Jørg. & Wedin (redirected from: Collema occultatum)
Family: Collemataceae
[Collema occultatum Bagl.,  more]
Rostania occultata image
Thallus: subcrustose-lobate or subfoliose, finally often ±pulvinate, small, usually up to 3 mm wide, rounded or becoming irregular or forming a thin, effuse crust lobes: few, small and short, 150-200 µm thick (when moist), smooth, ±radiating, contiguous or free, entire or somewhat divided, ±flat and appressed or terete and erect or becoming ±coralloid and forming small tufts upper surface: dark olive-green to black, dull, epruinose, semi-translucent when wet isidia: absent, but erect lobules appearing 'isidioid' lower surface: usually paler than the upper surface Apothecia: rather numerous, sometimes crowded, laminal on lobes or terminal on lobe tips, sessile with ±constricted base, small, 0.2-0.3(-0.5) mm wide, globose and perithecia-like when young disc: initially punctiform, later concave, dark red to black, dull, smooth, epruinose thalline margin: thin to thick, entire or somewhat verrucose or lobulate, finally receding proper exciple: rather thin, up to 40 µm wide, euparaplectenchymatous; cells: isodiametric, 8.5-22 µm wide hymenium: hyaline, 90-105 µm high asci: narrowly clavate or subcylindrical, 8-spored ascospores: ±cubic with rounded angles or subglobose, sub- to eumuriform, 13-22 x 9-15 µm Pycnidia: immersed, ±globose, pale conidia: bacilliform, 4-5 x c. 1 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on ±basic bark of Quercus and Platanus, also on Juniperus and wood, in forests and open woodlands World distribution: from arctic to Mediterranean areas of Europe and North America and extending to northern Africa Sonoran distribution: northern and southeastern Arizona, Baja California Sur, Sonora, and Sinaloa, in mountains, usually above 1000 m.