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Sphaerellothecium parmeliae Diederich & Etayo
Family: Mycosphaerellaceae
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Vegetative hyphae: brown, branched, 4-5 µm in diam., forming a superficial net on the host thallus, smooth-walled, BCr- Pseudothecia: black, semi-immersed to sessile, globose, 25-40(-60) µm in diam. wall: entirely dark brown, with pseudoparenchymatic hyphae (textura angularis), hyphae 2-5 µm wide and 4-7 µm long hamathecium: paraphysoids: not visible at maturity periphyses: short, simple, less than 10 x 1.5 µm asci: bitunicate, sessile, ellipsoid, 19-23 x 9-12.5 µm, 8-spored; epiplasma: in young asci I+ orange (dextrinoid reaction), with distinct ocular chamber ascospores: hyaline but rarely becoming pale brown when mature, 1-septate, with cells of equal size, slightly constricted at the septa, oval, 8.5-10 x 3-4 µm, with rounded apices, 1-2-seriate inside of the ascus; epispore: smooth, thin-walled, not halonate, BCr- Pycnidia: not observed. Hosts: the thallus of Parmelia saxatilis and P. sulcata, arising from large black necrotic areas World distribution: Asia (southern Siberia), Europe, and North America Sonoran distribution: known from one collection in southern California. Note: The pseudothecia of Sphaerellothecium parmeliae are found in large black areas of the host thallus and probably kill the host.