Amphibambusa aureae X. Zhou, K. Habib & Q. R. Li 2024, sp. nov.

Amphibambusa aureae X. Zhou, K. Habib & Q. R. Li sp. nov. Fig. 3 Etymology. Named after the host-specific epithet “ Phyllostachys aureae Rivière & C. Rivière ” from which the fungus was isolated. Type. China • Guangxi Zhuang Autonomous Region, Liangfengjiang Forest Park (22 ° 43 ' 24.91 " N, 108 ° 26 ' 56.39 " E), altitude: 99 m, on Phyllostachys aureae, 15 August 2023, Xin Zhou, Wenyu Zeng, 2023 LFJ 9 (GMB 4550, holotype; GMBC 4550, ex-type); ibid KUN-HKAS 134919, isotype. Description. Saprobic on dead culms of bamboo, forming black circular spots on the host surface. Sexual morph: Ascomata 660–860 μm wide, 520–630 μm high, immersed under host epidermis, solitary, scattered, globose to subglobose, visible as a black dot, ostiole at the center, with a neck, with an underdeveloped clypeus. Ostioles are centrally located, black, surrounded by white margin. Peridium 13–30 μm thick, outer brown to hyaline inner, cells textura angularis. Paraphyses 2–4.8 μm (x ̄ = 3.7 μm, n = 20) wide, longer than the asci, numerous, filamentous, colorless, branched, septate. Asci 90–190 × 9–18 μm (x ̄ = 148.5 × 13.1 μm, n = 20), 8 - spored, unitunicate, cylindrical, short-pedicellate, apically rounded, with a J + subapical ring, 1.4–1.9 × 2.5–3.6 μm (x ̄ = 1.7 × 3.1 μm, n = 6). Ascospores 15–22.5 × 5–7.9 μm (x ̄ = 19 × 6.6 μm, n = 40), L / W 3.4, 1–2 seriate, fusiform, subhyaline, 1 - septate in the middle, slight constricted at the septum, with round ends, with longitudinal striations along the entire length of the ascospore, and enveloped by a gelatinous sheath 2.5–7 μm (x ̄ = 5.2 μm, n = 20), lacking appendage. Asexual morph: Undetermined. Culture characteristics. Cultured on PDA medium at 27 ° C for 4–5 weeks, the colony diameter measures 4–4.5 cm, round, slightly raised in the center, with a neat margin. The mycelium at the colony edge is degraded, appearing white and glossy. A portion of the colony center is brown. Paratype. CHINA • Guangxi Zhuang Autonomous Region, Liangfengjiang Forest Park (22 ° 43 ' 20.90 " N, 108 ° 26 ' 33.52 " E), altitude: 99 m, on Phyllostachys aureae, 15 August 2023, Xin Zhou, Wenyu Zeng, 2023 LFJ 190 (GMB 4561; paratype; GMBC 4561, ex-paratype). Notes. In the phylogram, Amphibambusa aureae (ex-type: GMBC 4550) clustered in a distinct clade close to A. bambusicola D. Q. Dai & K. D. Hyde (ex-type: MFLLUCC 11–0617). The genus Amphibambusa is represented by two species, A. hongheensis H. B. Jiang & Phookamsak and A. bambusicola. Amphibambusa aureae shares similarities with both species, such as ascomata immersed in a black clypeus, ostiolar openings surrounded by a white margin, cylindrical asci with a J + subapical ring, and fusiform, longitudinally striated ascospores enveloped by a distinct mucilaginous sheath (Liu et al. 2015, Jiang et al. 2021 a). However, A. aureae can be distinguished from A. bambusicola by its smaller ascospores (15–22.5 × 5–7.9 μm compared to 25–27 × 5.5–6 μm in A. bambusicola) (Liu et al. 2015). Additionally, ascospores of A. aureae have rounded ends and are slightly constricted at the septum, whereas those of A. bambusicola have pointed end cells and are deeply constricted at the septum. Amphibambusa hongheensis differs from A. aureae by having smaller asci (118–160 × 14–18 μm vs. 90–190 × 9–18 μm) and larger ascospores (25.5–33 × 5.5–7.2 μm vs. 15–22.5 × 5–7.9 μm) (Jiang et al. 2021 a).