Neoroussoella bambusae Phookamsak, 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 : 23

Neoroussoella bambusae Phookamsak, J.K. Liu & K.D. Hyde , sp. nov. FIG. 14

Index Fungorum : IF550669

Etymology. Named for the host from where the fungus was isolated.

Saprobic on decaying bamboo culms. Ascostromata 120–175 µm high, 380–450 diam, immersed under a clypeus or epidermis, raised, visible as black dome-shaped or shield-shaped, or flattened ovoid areas on the host surface, coriaceous, solitary to gregarious, black, centrally ostiolate. Peridium 8.5–16.7 μm wide, composed of 2–3 layers of textura angularis, thin-walled flattened at the base, light brown to brown. Hamathecium comprising 1–1.8 μm wide, numerous, anastomosing cellular pseudoparaphyses, branching at the apex, smooth-walled, often constrict at the septum, and embedded in a gelatinous matrix. Asci 60–80(–82)(–85) × 5–6(–6.5) μm (x = 72.2 × 5.6 μm, n = 20), 8-spored, bitunicate, cylindrical, short to long pedicellate, apically rounded with an ocular chamber (0.4–0.8 μm). Ascospores (7.5–)8–10 × 3–4 μm (x = 9 × 3 μm, n = 30), uni-biseriate or overlapping, ellipsoidal to fusiform, 2-celled, constricted at the septum, pale brown to brown or yellowish brown, rough-walled, longitudinally ribbed, surrounded by a mucilaginous sheath. Ascospores germinating within 12 hours, initially from one cell, hyaline hyphae. Asexual morphs produced on bamboo pieces on WA after 2 months. Conidiomata 200–430 μm high, 300–420 μm diam, immersed to superficial, pycnidium, uni-multilocular, globose to subglobose or irregular in shape, scattered or clustered, solitary or gregarious, indistinctly ostiolate. Pycnidial wall 11–18 µm wide, composed of several layers of cells of textura angularis, 4–5 outer layers, thin-walled with elongated cells of textura angularis, light brown to brown, 2–3 inner layers, thick-walled, hyaline. Conidiophores arising from the basal cavity around the conidiomata, unbranched, aseptate. Conidiogenous cells (1.5–)3–6(–7) ×1–2 µm (x = 4 × 1.5 μm, n = 15), annellidic, unbranched, ampulliform or lageniform or cylindrical or cylindric-clavate, hyaline, aseptate, thin-walled, smooth-walled. Conidia 3–4 × 1.5–2(–2.5) μm (x = 3.5 × 2 μm, n = 35), oblong to ellipsoidal, hyaline, aseptate with two guttules, smooth-walled.

Specimen examined THAILAND, Chiang Rai, Phan District, Pukaeng Waterfall , on dead branch of Bambusa (Graminae) , 22 May 2010, R . Phookamsak, RP 0040 (holotype MFLU 11−0160 , ex-type living culture MFLUCC 11−0124 ) .

Notes: Neoroussoella is described herein as a monotypic genus represented by N. bambusae , collected on dead bamboo culms in Thailand. This taxon is characterized by its semi-immersed to immersed solitary ascostromata, cylindrical asci and relatively small brown, longitudinally ribbed two-celled ascospores. The asexual morph (formed in culture) has small, hyaline conidia with smooth walls. The genus forms a basal monotypic clade in the family Roussoellaceae ( FIG. 1).