Pseudoasteromassaria fagi Matsumura & Kaz. Tanaka, sp. nov.
Index Fungorum number: IF551435; Facesoffungi number: FoF00964; Fig. 1
Etymology – In reference to the host genus Fagus.
Holotype – HHUF 30471

Parasitic on twigs of Fagus crenata Blume. Sexual morph: Ascomata 250 – 310 μm high, 700 – 760 μm diam., mostly scattered, immersed, compressed globose in section, with central, papillate ostiole. Peridium 37.5 – 50 μm wide at the base, 45 – 100 μm wide at the sides, composed of two strata; outer stratum thin, composed of dark brown cells; inner stratum composed of 4 – 7 layers of hyaline, angular cells (7.5 – 15 × 5 – 13 μm). Hamathecium comprising numerous, 1 – 2.5 μm wide, hyaline, septate, branched, cellular pseudoparaphyses. Asci 139.5 – 195.5 × 35 – 40 μm (x̄ = 168.1 × 36.7 μm, n = 10), 8 – spored, bitunicate, fissitunicate, cylindric to clavate, pedicellate (24.5 – 38.5 μm long), apically rounded, with an ocular chamber. Ascospores 38.5 – 47 × 11 – 15 μm (x̄ = 43.5 × 13.3 μm, n = 20), L/W 2.9 – 3.8 (x̄ = 3.3, n = 20), 2 – 3 overlapping seriate, brown, fusiform, mostly straight, 1 – 3 – septate, thick-walled, verrucose, with a prominent surrounding sheath. Asexual morph: Conidiomata pycnidial, 230 – 340 μm high, 140 – 240μm diam., scattered, immersed or superficial, globose, ostiolate. Peridium 30 – 52.5 μmwide, composed of 2 strata; outer stratum composed of 3 – 5 layers of polygonal, brown to pale brown cells (8 – 17.5 × 5 – 10 μm); inner stratum composed of 2 – 3 layers of polygonal, hyaline cells (8 – 10 × 4.5 – 6 μm). Conidiophores absent. Conidiogenous cells 6 – 16 × 5 – 7 μm, enteroblastic, phialidic, doliform to ampulliform. Conidia (52–) 61 – 71 × 10 – 12.5 μm (x̄ = 66.1 × 11.6 μm, n = 20), L/W (4.3–) 5.1 – 7.0 (x̄ = 5.8, n =  20), cylindric, truncate at the base, 6 – 7-septate, hyaline, smooth-walled, lacking a sheath.

Material examined – JAPAN, Aomori, Towada, Tsuta hotspring, on twigs of Fagus crenata (Fagaceae), 6 November 2011, K. Tanaka, KT 2966 (HHUF 30471, holotype designated here); living culture, MAFF 245221; Kagoshima, Tarumizu, Mt. Oonogara, on twigs of Fagus crenata, 25 October 2013, K. Tanaka, KT 3432 (HHUF 30472, paratype), ex-type living culture, MAFF 245222.

Fig. 1 Pseudoasteromassaria fagi (a, b, f – j HHUF 30472; c – e, k HHUF 30471 holotype; l, m, p, s, u culture MAFF 245222; n, o, q, r, t culture MAFF 245221) a, b Appearance of ascomata on host surface c Ascoma in longitudinal section d Peridium e Pseudoparaphyses f, g Asci h Ascus apex i – l Ascospores m Germinating ascospore n, o Conidiomata on rice straw in culture p Conidioma in longitudinal section q Peridium r Conidiogenous cells s – u Conidia. Scale bars: a, b, n = 500 μm, o = 200 μm, c, p = 100 μm, d – m, q – u = 10 μm.