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Parmotrema dilatatum (Vainio) Hale
Family: Parmeliaceae
[Parmelia dilatata Vain.]
Parmotrema dilatatum image
Stephen Sharnoff  
Thallus: foliose, adnate to loosely adnate, 3-20 cm in diam., lobate lobes: subirregular, elongate, slightly imbricate, plane, separate, 10-20 mm wide; apices: rotund, eciliate or short cilia developing in the axils of the lobes upper surface: gray with some blackened areas, smooth, usually shiny, emaculate to faintly white maculate, reticulately cracked with age soredia: granular, common, marginal, in linear soralia that sometimes develop on marginal lacinae; isidia and pustulae: absent medulla: white or pigmented pale yellowish pink, with continuous algal layer lower surface: black with brown to mottled ivory naked zone peripherally, centrally rhizinate; rhizines: scattered, simple Apothecia: rare, substipitate, up to 10 mm in diam.; margin: sparsely sorediate; disc: brown, imperforate ascospores: ellipsoid, 18-22 x 8-10 ┬Ám Pycnidia: not seen Spot tests: upper cortex K+ yellow, C-, KC-, P-; medulla K-, C-, KC-, P+ red Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with protocetraric acid (major), echinocarpic and conechinocarpic acids (minor or trace), secalonic acid A (+ trace). Substrate and ecology: usually on trees in open habitats, rarely on rocks World distribution: pantropical and SE USA and SW Europe Sonoran distribution: Sinaloa, in the Sierra Madre Occidental.