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Thelopsis isiaca Stizenb.
Family: Stictidaceae
Thelopsis isiaca image
André Aptroot  
Thallus: crustose, endophloeodal, or rarely developing as thin to thick thallus over the substrate, when well developed becoming rimose to warty areolate (areoles up to 1 mm wide) upper surface: (if evident) light gray or pale lime colored, smooth to rugose Perithecia: subglobose, somewhat flattened above, 0.4-0.5 mm wide, partially immersed; exciple: colorless, c. 30 µm wide; hymenium: hyaline or pale brown, I+ blue-green, rapidly changing to red-brown; periphyses: up to 25 µm long and c. 1 µm wide; paraphyses: slender, septa best seen in I, c. 280-300 x 1.5 µm, flexuose asci: narrowly cylindrical, tapering apically, thin-walled, without apical thickening or apparatus, 200-250 x 10-12 µm, 100 to 150-spored ascospores: ellipsoid, becoming 1-septate, colorless, halonate, 12-15 x 5-8 µm Pycnidia: immersed conidia: ellipsoid to ovoid, c. 3-5 x 1-1.5 µm Spot tests: thallus K-, C-, KC-, P- Secondary metabolites: none detected. Substrate and ecology: on trees (Umbellularia californica) in open habitats and also on acidic rocks World distribution: southern Europe, Egypt and southern California Sonoran distribution: Santa Monica Mountains and the Channel Islands of southern California, and mountainous areas of Sonora and Chihuahua. Notes: A careful comparison of Mediterranean and Sonoran material of the this species revealed that the Sonoran specimens fall well within the range of variation of the old world material with respect to pycnidial and thallus characters. Prof. E. Barreno reports one specimen from Spain with filiform conidia.