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Verrucaria rufofuscella Servft
Family: Verrucariaceae
Verrucaria rufofuscella image
Othmar Breuss  
Thallus: rimose-areolate, 0.20-0.35 mm thick, with broad obtuse fissures, thinning marginally, peripheral parts broken up into smaller dispersed areoles, with or without a pale prothallus areoles: subangular to irregularly roundish-angular, plane, 0.3-0.7(-1) mm wide, margins partly subascending and finely crenulate surface: dark brown to reddish brown, dull, uneven anatomy: upper cortex not discernible but uppermost cell layer pale brown, sometimes overlain by a very thin epinecral layer; algal layer: irregular, 80-120 µm thick, with algal cells 7-11 µm in diam., mycobiont portion subparaplectenchymatous, inspersed with crystals; medulla: colorless to pale brown, obscured by substrate grains Perithecia: 1(-3) per areole, immersed, the apical part protruding, bare, black; exciple: (sub)globose, 0.25-0.40 mm wide, 15-25 µm thick, blackening, basal part often pale; involucrellum: appressed to the exciple, extending down to the base level of perithecium and ± incurved beneath the exciple, apically and laterally 30-40 µm thick, at base thinning or diffusely pigmented; periphyses 20-30 µm long, simple asci: clavate, 70-90 x 25-33 µm, 8-spored ascospores: hyaline, simple, ellipsoid, 20-25 x 11-13 µm Pycnidia: unknown Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: epilithic, on sandstone and shale World distribution: Europe (Germany) Sonoran distribution: collected by H.E.Hasse and recently found by K.Knudsen in the Santa Monica Range in California. Notes: Verrucaria rufofuscella is one out of many "forgotten" species described by M. Servít. In overall appearance Verrucaria rufofuscella resembles V. fuscoatroides, which differs mainly in having a considerably thicker involucrellum.