Ascomata small, globose to subglobose, black, coriaceous. Peridium composed of large lightly pigmented cells of textura angularis. Hamathecium of rare, broad pseudoparaphyses, septate, constricted at the septa. Asci bitunicate, fissitunicate, broadly cylindrical to slightly obclavate, with a short, thick, knob-like pedicel. Ascospores hyaline, 1- (rarely 2-) septate. Anamorphs reported for genus: none. Literature: von Arx and Müller 1975; Barr 1972; Clements and Shear 1931; Eriksson 2006; Lumbsch and Huhndorf 2007; Theissen and Sydow 1915. Type species Metameris japonica (Syd.) Syd., Annls mycol., 13(3–4): 342 (1915). (Fig. 59)
Fig. 59 Metameris japonica (from S, F7166, type). a Ascostroma arrangement on the host surface. b Section of two ascomata from one ascostroma. c Immature asci within pseudoparaphyses. see more d, e Hyaline ascospores. Scale bars: a = 0.5 mm.
b = 100 μm, c–e = 20 μm ≡ Monographus japonicus Syd. Annls mycol. 10: 408 (1912). Ascostromata erumpent through the host surface in linear rows parallel to the host fibers, 500–750 μm long and 140–200 μm wide, with three to ten ascomata arranged in a line (Fig. 59a). Ascomata 115–160 μm diam., semi-immersed in substrate to erumpent, globose, subglobose, black, coriaceous (Fig. 59b). Cells of ascostromata heavily pigmented and thick-walled, cells of peridium composed of large lightly pigmented cells of textura angularis, cells 5–15 μm diam., cell wall <1 μm thick, peridium thicker at the base, up to 50 μm (Fig. 59b). Hamathecium of rare, pseudoparaphyses 3–4 μm broad, septate, constricted GW786034 mouse at the septa, anastomosing or branching not observed. Asci (65-)80–90 × 12–15 μm (\( \barx = 82.8 \times 13.3\mu m \), n = 10), 8-spored, bitunicate, fissitunicate, broadly cylindrical to slightly obclavate, with a short, thick, knob-like pedicel, lacking an ocular chamber (Fig. 59c). Ascospores 25–30 × 5–6 μm (\( \barx = 27.4 \times 5.6\mu
m \), n = 10), biseriate, oblong, hyaline, 1-2-septate, the secondary septum exclusively occurring in the Thymidine kinase upper cells, slightly constricted at the primary septum which is slightly below the centre of the ascospore, the upper cells usually swollen near the main septum (Fig. 59d and e). Anamorph: none reported. check details Material examined: JAPAN, Province Mino. on Osmunda regalis L. var. japonica Milde., 10 May 1912, R. Hale (S, F7166, type, as Monographos japonicus Syd.). Notes Morphology Metameris was formally established by Theissen and Sydow (1915) to accommodate Monographus japonicus Syd., which is characterized by the erumpent ascomata arranged in linear ascostromata, the presence of pseudoparaphyses and hyaline 2-septate ascospores. Clements and Shear (1931) assigned it to Dothideaceae (subfamily Dothideae), and von Arx and Müller (1975) assigned it to Pleosporaceae. Currently, it is considered as a member of Phaeosphaeriaceae (Pleosporales) (Eriksson 2006; Lumbsch and Huhndorf 2007).
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