Roussoella thailandica D.Q. Dai., 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 : 20

Roussoella thailandica D.Q. Dai., J.K. Liu & K.D. Hyde. , sp. nov. FIG. 12

Index Fungorum : IF550666

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

Saprobic on decaying bamboo culms. Ascostromata 1−1.5 mm diam., semi-immersed or immersed under a clypeus, raised, visible as black, dome-shape areas on host surface and becoming tumefied on maturity. Locules 70−100 µm high, 350−500 µm diam., solitary to gregarious, subglobose to ellipsoidal, dark brown, with an inconspicuous central ostiole. Peridium 10−15 µm wide, comprising host and fungal tissues, thin, composed of dark brown cells of textura angularis. Hamathecium comprising 1.5−2 µm wide, numerous, anastomosing, cellular pseudoparaphyses, branching, rough-walled, and embedded in a gelatinous matrix. Asci (83−)95−120(−133) × (6.5−)7−9 µm (x = 106.6 × 8.1 µm, n = 20), 6−8-spored, bitunicate, cylindrical, with a short branched knob-like pedicel, with an indistinct apical chamber. Ascospores 13.5−15.5(−16) ×4.5−6 µm (x = 14.5 × 5.5 µm, n = 30), uni-seriate, occasionally biseriate, ellipsoid to broad fusiform, 2-celled, constricted at the septum, upper cells bigger, occasionally curve, narrowly at both ends, with irregular longitudinal striations.

Specimen examined. THAILAND, Chiang Rai Province, Doi Pui , on dead culms of bamboo, 1 Sep 2011, D. Q Dai, DDQ−0113 (holotype MFLU 13−0640 , ex-type living culture MFLUCC 11−0621 ) .

Notes: Roussoella thailandica formed a sister group with R. nitidula , but differs in having smaller asci and ascospores (asci 95−120 × 7−9 µm vs. 110–200 × 8–11 μm; ascospores 13.5−15.5 ×4.5−6 µm vs. 16–19 × 5.5–7 μm).