Roussoella japanensis Kaz. Tanaka, J.K. Liu & K.D. Hyde, 2014

Liu, Jian-Kui, Phookamsak, Rungtiwa, Dai, Dong-Qin, Tanaka, Kazuaki, Jones, Gareth, Xu, Jian-Chu, Chukeatirote, Ekachai & Hyde, Kevin D., 2014, Roussoellaceae, a new pleosporalean family to accommodate the genera Neoroussoella gen. nov., Roussoella and Roussoellopsis, Phytotaxa 181 (1), pp. 1-33 : 14-15

Roussoella japanensis Kaz. Tanaka, J.K. Liu & K.D. Hyde , sp. nov. FIG. 7

Index Fungorum : IF550663

Etymology. Named after the country from where this fungus was collected, Japan.

Saprobic on decaying bamboo culms. Ascostromata 0.5–2 mm diam., immersed under a clypeus, raised, visible, black, dome-shape areas on host surface, uni-biloculate. Locules 190–210 µm high, 500–560 µm diam, depressed globose with a flattened base, single or 2–3 grouped, ostiolate. Beak short papillate, 38–50 µm high, 50–85 µm wide. Peridium 10–15 µm thick at sides, composed of 3–5 layers of polygonal flattened cells (3.5–12.5 × 1.5–2.5 µm), surrounded by wedge-shaped stromatic region (450–800 µm wide at sides) composed of rectangular to polygonal cells (3.5–15 × 4–10 µm). Hamathecium comprising 1–1.5 µm wide, numerous, anastomosing, cellular pseudoparaphyses, branching, rough-walled, and embedded in a gelatinous matrix. Asci 107–132 × 8–9.5 µm, 8-spored, bitunicate, cylindrical, short pedicellate (10–13 µm). Ascospores 16–22 × 5.5–7 µm (x = 19 × 6.5 µm, n = 50), uniseriate, fusiform to ellipsoidal, with a median septum, 2-celled, brown, covered with longitudinal striations and surrounded by an entire sheath of 0.5–4 µm wide. Conidiomata in culture, 300–550 µm high, 900–2000 µm diam, depressed globose, single to grouped, immersed. Peridium 7–12.5 µm wide. Conidiophores absent. Conidiogenous cells phialidic, ampulliform. Conidia 9.5–13 × 4–5 µm, oblong-ellipsoidal, yellowish brown, warty.

Specimen examined. JAPAN, Kanagawa, Yokohama, Nakaku, Sankei-garden , on twigs of Sasa veitchii var. veitchii ; 9 Mar 2004; K . Tanaka & Y . Harada, KT 1651 (holotype HHUF 29217 , ex-type living culture JCM 13126 = MAFF 239636 ) .

Notes: Although Roussoella japanensis produced an asexual morph similar to that of R. hysterioides , the asci and ascospores are considerably smaller than those of R. hysterioides (asci 107–132 × 8–9.5 µm vs. 140–210 × 8–11 µm; ascospores 16–22 × 5.5–7 µm vs. 18–34 × 6–8 µm). Tanaka et al. (2009) identified two Roussoella specimens ( HHUF 26988 and KT 1651) as R. hysterioides , but sequence similarity between these fungi is very low (ca. 90.6%) in their ITS regions (Tanaka, unpublished data).

Figures

FIGURE. 7 Roussoella japanensis. a, b. Ascostromata on host surface; c, d. Section of ascostromata; e. Wedge-shaped stromatic region; f. Peridium; g. Pseudoparaphyses; h, i. Asci; j–m.Ascospores (m in indian ink); n. Section of conidioma; o. Conidia; a−m from KT 1651 (= HHUF 29217); n, o from culture JCM 13126 = MAFF 239636. ─ Scale bars: a, b = 1 mm; c = 500 µm; d, n = 100 µm; e−i = 20 µm; j−m, o = 5 µm.