Bambusicola ellipsospora Y. Feng, Z. Y. Liu & Jian K. Liu 2025, sp. nov.

Bambusicola ellipsospora Y. Feng, Z. Y. Liu & Jian K. Liu sp. nov. Fig. 2 Holotype. HKAS 112592. Etymology. The epithet refers to the ellipsoidal ascospores. Description. Saprobic on dead bamboo culms. Sexual morph: Ascomata 215–363 μm diam., 180–288 μm high, solitary, scattered to gregarious, immersed to erumpent, later becoming superficial, forming brown to dark brown, lenticular spots on the host surface with a slit. Peridium comprising several layers of cells of textura angularis, inner layers comprising hyaline to dark brown, outer layers composed of thick, dark brown to black cells. Hamathecium of dense, 0.5–1.8 μm wide, filamentous, branched, septate, smooth-walled, trabecular pseudoparaphyses, anastomosing at the apex, embedded in a hyaline, gelatinous matrix. Asci 70–92 × 15–21 μm (x ̄ = 82 × 17 μm, n = 20), 8 - spored, bitunicate, fissitunicate, broadly cylindrical to cylindri-clavate, with a short pedicel, apically rounded with a well-developed ocular chamber. Ascospores (18 –) 19–24 (– 25) × (5 –) 6–8 (– 9) μm (x ̄ = 22 × 7 μm, n = 30), overlapping, biseriate, hyaline, straight, ellipsoidal to fusiform, with obtuse ends, 1 - septate, constricted at the septum, smooth-walled with 4 large guttules, surrounded by a thin-gelatinous sheath. Asexual morph: Undetermined. Culture characteristics. Ascospores germinating on PDA within 12 h. Colonies on PDA slow growing, 13 mm diam. after 10 d at 25 ° C in the dark, circular, white, velvety, with dense mycelium on the surface; in reverse brown in the center, becoming paler to white at the entire margin. Material examined. China • Guizhou Province, Chishui City. On dead culms of bamboo, 10 July 2019, Yao Feng CS 018 (HKAS 112592, holotype; GZAAS 21-0503, isotype), ex-type living cultures CGMCC 3.20356 = GZCC 21-0803; ibid., CS 036 (GZAAS 21-0391, paratype), living culture GZCC 21-899. Notes. Phylogenetic analyses revealed that the two strains of Bambusicola ellipsospora (CGMCC 3.20356 and GZCC 21-0899) formed a distinct clade, sister to B. autumnalis (CGMCC 3.24280, CGMCC 3.20354, GZCC 21-0897) (Fig. 1). Bambusicola ellipsospora can be distinguished from B. autumnalis based on sequence divergence in tef 1 - α (874 / 927 bp) and rpb 2 (699 / 784 bp). Additionally, morphological differences further support their distinction, as B. ellipsospora produces ellipsoidal to fusiform ascospores with obtuse rounded ends, while B. autumnalis has fusiform and slightly curved ascospores with narrower acute ends (Liang et al. 2023). Moreover, the ascospore of B. ellipsospora collected in this study shows distinct constriction at the septum, whereas that of B. autumnalis only has slight constriction. Based on morphological and phylogenetic evidence, B. ellipsospora is recognized as a novel species.