Didymocyrtidium nudum Vain., Acta Soc. Fauna Flora fenn. 49(no. 2): 229 (1921) Fig. 49
MycoBank number: MB 557075; Index Fungorum number: IF 557075; Facesoffungi number: FoF 07131;
Saprobic on growing stems of Betula sp. Sexual morph: Ascomata 29–40 µm high × 36–43 µm diam., ( x = 38.2 × 39.9 µm, n = 10), semi immersed to superficial on host surface, simple, visible as dark brown to black circle on host surface. Peridium 9–11 µm wide thick-walled, composed of several layers of dark-brown cells of textura angularis. Hamathecium 2–3 µm wide present, with cellular pseudoparaphyses, anastomosing, branching, embedded in mucilaginous matrix, sometimes aparaphysate, covering asci by gelatinous matrix. Asci 30–32 µm × 16–18 µm ( x = 31.4 × 17.4 µm, n = 10), bitunicate, fissitunicate, 8-spored, ovoid to saccate, sessile with indistinct ocular chamber, thick-walled. Ascospores 10–12 µm × 3–4 µm ( x = 11.5 × 3.9 µm, n = 10), bi-to tri-seriated, or overlapping, oblong to cylindrical or ellipsoid, hyaline to subhyaline 1- septate, very slightly constricted at the septum, smooth or rough-walled. Asexual morph: Undetermined.
Material examined – RUSSIA, on stems of Betula sp. (Betulaceae), 16 July 1928, E. Häyrén (H6022676, syntype)
Economic significance – None is reported.