Seriascoma Phookamsak, D.Q. Dai & K.D. Hyde, gen. nov. Index Fungorum number: IF552014

Etymology: The generic epithet ^Seriascoma^ refers to the elongate rows of ascomata which form on the host surface.

Saprobic on bamboo culms. Sexual morph: Ascostromata gregarious, clustered, immersed beneath clypeus, coriaceous, raised, erumpent in linear rows, with slit-like opening, multiloculate, ostiolate. Locules arranged in rows, immersed, clustered, gregarious, subglobose to ampulliform, or quadrilateral, glabrous, central ostiole with minute papilla. Peridium thick walled, composed of several layers of small, dark brown pseudoparenchymatous cells of textura angularis. Hamathecium composed of broad, filamentous, distinctly, septate, cellular, pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate clavate, long pedicellate, apically rounded, with well-developed, ocular chamber. Ascospores overlapping, uni- to tri-seriate, clavate to fusiform, with rounded ends, hyaline, 1-septate, slightly constricted at the septum, straight to curved, smooth-walled, with guttules. Asexual morph: Coelomycetous, Conidiomata eustromatic, solitary to gregarious, immersed in cortex layers, raised, black, elongate on bamboo pieces, conical, uni-loculate, glabrous, covered by vegetative hyphae. Wall of conidiomata comprising host and fungi tissue, with several layers composed of dark brown to black, textura angularis pseudoparenchymatous cells. Conidiophores arising from the basal cavity, reduced to conidiogenous cells. Conidiogenous cells holoblastic, phialidic, determinate, discrete, cylindrical to ampulliform or lageniform, hyaline, aseptate, apically attenuated, with distinct periclinal thickening, smooth-walled. Conidia oblong, with rounded to obtuse ends, hyaline, aseptate, smooth-walled.

Type species: Seriascoma didymospora Phookamsak, D.Q. Dai & K.D. Hyde

Notes: Seriascoma is introduced to accommodate Dothideomycete species forming elongated, multiloculate, coriaceous ascostromata, embedded beneath a clypeus, erumpent and splitting the host epidemis parallel with the veination to form a slit like opening. The ascospores are didymosporous, clavate to fusiform andhyaline. The genus iscommonly found on bamboo. Seriascoma morphologically differs from other genera in the family Occultabambusaceae in the position of its ascostromata under a clypeus. The asexual morph of Seriascoma is also different from Occultabambusa and Versicolorisporium. Seriascoma has hyaline, oblong, aseptate conidia, similar to Occultabambusa, but the conidia of Seriascoma (4.9 × 1.9 μm) are smaller than Occultabambusa (16.5 × 5.2 μm). Versicolorisporium forms brown, clavate and septate conidia. Based on multi-gene analyses (Fig. 13), Seriascoma forms a robust clade, close to Neooccultabambusa (Doilom et al. 2016). Ascostroma of Seriascoma are similar to those of Apiospora which are commonly found on bamboo. However, Apiospora hasunitunicate asci and belongs to Sordariomycetes (Senanayake et al. 2015).