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Verrucaria cetera Breuss
Family: Verrucariaceae
Verrucaria cetera image
Gerhard Neuwirth  
Life habit: lichenicolous, starting on Staurothele but may become independent Thallus: chinky areolate, without a prothallus areoles: angular to somewhat rounded, rarely slightly incised (especially those at thallus margin), close together, flat or slightly convex, 1-2 mm wide, 0.2-0.4 mm thick, basally ±constricted, anchored by a broad central hyphal bunch up to 0.6 mm long, free marginal parts of underside pale brown to black, surface: pale gray, dull, rather roughly pruinose anatomy: with an upper cortex 15-20 µm thick, composed of small roundish angular cells 4-6 µm in diam., outer cell layer pale brown, overlain by a 20-40 µm thick amorphous layer, lacking a cortical layer along the lateral walls of areoles; algal layer: continuous, algal cells 7-10 µm in diam.; alga-free medulla: subparaplectenchymatous, partly with filamentous parts especially near the stipe-like attachment organ formed by longitudinally arranged hyphae with small substrate particles in between Perithecia: immersed within the thallus, one to few per areole, entirely sunken into the areoles or with slightly emergent tips; exciple: subglobose to broadly pyriform, 0.3-0.4 mm wide, pale at first and black only around the ostiole, then darkening throughout; involucrellum: appressed, covering at least the upper half of perithecia, later extending to base of exciple and sometimes enveloping the whole perithecium; periphyses 35-50 µm long, 2-3 µm thick asci: clavate, 70-90 x 20-25 µm, 8-spored ascospores: hyaline, simple, ellipsoid, 20-27 x 9-13(-14) µm Pycnidia: immersed, 50-80 µm wide, visible as small black irregular dots often in small depressions of the areoles conidia: bacilliform, often slightly curved, 7.5-12 µm long Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on Staurothele areolata initially but becoming epilithic over conglomerate, limestone or sandstone World distribution: southwestern North America Sonoran distribution: Arizona (Coconino and Pinal Counties), and southern California (San Miguel Island). Notes: Verrucaria cetera is one out of three very similar lichenicolous species. For differences see under Verrucaria bernardinensis and V. inficiens.