Pallidoperidium yunnanense Q. R. Li 2026, sp. nov.

Pallidoperidium yunnanense Q. R. Li sp. nov. Fig. 4 Etymology. The specific epithet “yunnanense” refers to the Yunnan Province, where the holotype specimen was collected. Type. China • Yunnan Province, Zhaotong city, Yongshan county, Wumengshan National Nature Reserve, 28°19'29.72"N, 104°00'11.55"E, altitude: 1228 m, on dead bamboo, June 2024, collected by Xingyu Luo, WMS 149 (GMB 6414, holotype; KUN -HKAS 151614, isotype; GMBC 6414 ex-holotype culture). Paratype. • Yunnan Province, Zhaotong city, Yongshan county, Wumengshan National Nature Reserve, 28°19'29.36"N, 104°00'10.28"E, altitude: 1300 m, on dead bamboo, June 2024, collected by Xingyu Luo, WMS 614 (GMB 6415, paratype; GMBC 6415, ex paratype culture). Description. Saprobic on dead bamboo. Teleomorph: Ascomata 293–433 µm high, 446–700 µm diam., perithecial, deeply immersed in host tissue, solitary, subglobose. Ostiolar neck conical to cylindrical, 175–233 µm diam., periphysate. Ascomatal wall 15-56 µm thick, composed of 3-5 layers of elongate cells of 5–8.8 × 2–3 µm, hyaline at the inside, pale brown towards the outside. Paraphyses 1.7–3 µm wide, numerous, septate, unbranched, cylindrical, hyaline. Asci 118–151 × 6.7–10.3 µm (x ̄ = 130 × 8.5 µm, n = 20), 8 - spored, unitunicate, cylindrical, with a short stipe, with apical apparatus not bluing in Melzer’s reagent. Ascospores 14.4–18 × 5.5–7.3 µm (x ̄ = 16 × 6.4 µm, n = 30), l / w = 2.5, uniseriate, ellipsoid to fusiform, unicellular, brown, surrounded by a narrow mucilaginous sheath. Anamorph: Not observed. Habit and habitat. Scattered on dead bamboo. Notes. Morphologically, Pallidoperidium yunnanense resembles P. exasperatum R. Sugita & Kaz. Tanaka and P. paraexasperatum R. Sugita & Kaz. Tanaka, in having immersed perithecial ascomata, cylindrical unitunicate asci with a discoid apical apparatus, and brown, ellipsoid to fusiform ascospores. However, P. yunnanense differs from P. exasperatum by having markedly broader ascomata (446–700 µm vs. 320–390 µm wide) and ascospores with a narrow mucilaginous sheath (vs. ascospores with a thick mucilaginous sheath) (Sugita et al. 2024). P. yunnanense is distinguished from the additional two species in the genus by its smaller, narrower ascospores (14.4–18 × 5.5–7.3 µm) compared to P. chinense (18–35 × 5–9.5 µm) and P. smilacis (16.3–18.3 × 7.7–8.4 µm). In addition, P. chinense and P. smilacis have smooth to roughened ascospores with a thick mucilaginous sheath, while mucilaginous sheath narrow in P. yunnanense (Habib et al. 2025). Phylogenetically, Pallidoperidium yunnanense forms an independent clade in a basal position within the genus. Although phylogenetically distinct, its morphology is consistent with the generic concept of Pallidoperidium, including subglobose, deeply immersed perithecial ascomata, discoid apical apparatus, and ellipsoid to fusiform brown ascospores (Table 2).