Roussoella intermedia Y.M. Ju, J.D. Rogers & Huhndorf, Mycotaxon

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 : 13-14

Roussoella intermedia Y.M. Ju, J.D. Rogers & Huhndorf, Mycotaxon 58: 447. 1996. FIG. 6

Saprobic on decaying bamboo culms. Ascostromata 0.8–1.6 mm wide, 1.7–4.9 mm long, immersed under a clypeus, raised, visible, black, dome-shape areas on host surface, uni-biloculate. Locules 280–400 µm high, 450–630 µm diam, subglobose to lenticularis with a flattened base, solitary to clustered, black, centrally ostiolate. Beak short papillate, 75–95 µm high, 60–80 µm wide. Peridium 17–25 µm thick at sides, composed of polygonal flattened cells (5–12.5 × 1.5–5 µm), surrounded by wedge-shaped stromatic region (350–600 µm wide at sides) composed of rectangular to subglobose cells (5–20 × 2–15 µm). Hamathecium comprising 1–2 µm wide, numerous, anastomosing cellular pseudoparaphyses, branching, rough-walled, and embedded in a gelatinous matrix. Asci (86–)92–117(–130) × 6–8 µm (x = 104.5 × 6.5 µm, n = 20), 8−spored, bitunicate, cylindrical, short pedicellate(12.5–29 µm long). Ascospores 12–18 × 4–5 µm (x = 14.8 × 4.5, n = 50), uni-seriate, fusiform to cylindrical, with a median septum, 2-celled, brown, with irregular longitudinal striations. Asexual morph did not form in culture.

Specimen examined. JAPAN, Hokkaido, Isl. Rishiri, Oniwaki mountain trail, on twigs of Sasa kurilensis , 29 July 2007, K . Tanaka & G . Sato, KT 2303 (= HHUF 30025 ), living culture NBRC 106245 .

Notes: Roussoella intermedia is similar to R. pustulans , but differ in having larger asci and ascospores (asci 92–117 × 6–8 vs. 68–83 × 6.5–8.5 µm; ascospores 12–18 × 4–5 vs. 10–16 ×4–5 µm). The combined sequences phylogenetic tree (FIG. 1) indicates that these two species could be probably the same fungus. However, the ITS sequences analysis confirms that they are phylogenetically distinct species (FIG. 2).

Figures

FIGURE. 6 Roussoella intermedia (HHUF 30025). a, b.Ascostromata on host surface; c, d. Section of ascoma; e. Wedge-shaped stromatic region; f. Peridium; g. Pseudoparaphyses; h, i. Asci; j–r. Ascospores; s. Germinating ascospore. ─ Scale bars: a, b = 1 mm; c = 500 µm; d = 100 µm; e–i, s = 20 µm; j–r = 5 µm.