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Peltula placodizans (Zahlbr.) Wetmore
Family: Peltulaceae
[Endocarpiscum placodizans (Zahlbr.) Fink,  more]
Peltula placodizans image
Harrie Sipman  
Thallus: squamulose, ± placodioid, areolate in center, lobate at margins central squamules: upright, cylindrical, roundish, flat or convex, 0.1-0.5 in diam., marginal lobes: 0.2-0.5 mm wide and up to 1.3 mm long upper surface: brownish to olive-green soredia: farinose, black, in capitate soralia (often on top of the central squamules upper cortex: not developed but with a yellow epinecral layer (8-15 µm thick) medulla: composed of loosely interwoven hyphae with globose cells and numerous air spaces; algal layer: 50-90 µm thick lower cortex: poorly developed, 20-40 µm thick, paraplectenchymatous with globose hyphal cells (3-8 µm in diam.) lower surface: paler than the upper surface, Apothecia: rare, normally one per squamule, restricted to central squamules, immersed with punctiform discs; disc: yellowish brown to blackish brown, up to 0.3 mm diam.; epihymenium: yellowish brown, K+ red-violet or K-; hymenium: I+ wine-red, 90-120 µm high asci: clavate to obclavate; hymenium: wine red in iodine; wall: I+ orange but blue after pretreatment with K, >64-spored ascospores: globose to ellipsoid, 4.5-8 x 3-4.5 µm Pycnidia: immersed, simple, spherical conidia: fusiform, 3.5 x 1.5 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on acidic rocks, frequently in places that receive some shade in deserts and other open, arid habitats World distribution: South America, SW North America, Africa, Australia and Europe Sonoran distribution: desert areas and lower elevation forests of Arizona, southern California, Sonora, Sinaloa, and Baja California Sur.