Xylaria acifer Xiao Y. Pan, 2025

Pan, Xiaoyan, Chen, Zongzhu, Chen, Yiqing, Lei, Jinrui, Chen, Xiaohua, Wu, Tingtian & Li, Yuanling, 2025, Two new species of Xylaria (Xylariaceae, Ascomycota) associated with fallen leaves in Hainan Tropical Rainforest National Park, China, MycoKeys 112, pp. 17-34 : 17-34

Xylaria acifer Xiao Y. Pan sp. nov.

Fig. 2

Holotype.

China • Hainan Province, Diaoluoshan Area of Hainan Tropical Rainforest National Park ; 18°43'35"N, 109°52'11"E; elevation 973 m; on fallen leaves, 18 June 2023, Xiaoyan Pan ( HAFFR 122 ). GenBank accession numbers PQ 483147 (ITS), PQ 498329 ( TUB 2 ), and PQ 498326 ( RPB 2 ).

Diagnosis.

Differs from X. hedyosmicola by its smaller ascospores. Differs from X. vittatipiliformis by the absence of band-like stripes on its stromata surfaces and its smaller ascospores. Differs from X. vittiformis by the absence of band-like stripes on its stromata surfaces.

Etymology.

“ acifer ” refers to the needle-like shape of the stromata.

Teleomorph.

Stromata upright, solitary, needle-like, unbranched, 25–50 mm total length; acute sterile apex, 2–10 mm; fertile portion 3–10 mm long × 0.8–1.2 mm diam., elongate cylindrical, composed of tightly arranged perithecia; stipe glabrous, 15–40 mm long × 0.5–1 mm diam., longitudinally striate, the base slightly swollen; surface roughened, black, with conspicuous to half-exposed perithecial mounds; interior white to creamy; texture soft. Perithecia spherical, 250–500 µm diam. Ostioles papillate. Asci with eight ascospores arranged in uniseriate manner, cylindrical, 90–150 µm total length, spore-bearing part 60–85 µm long × 5.5–7.5 µm wide, stipe 30–70 µm long, with a bluing apical ring in Melzer’s reagent, tubular to slightly urn-shaped, 1.8–3.5 µm high × 1.4–2.5 µm diam. Ascospores brown to dark brown, unicellular, ellipsoid to fusiform, inequilateral, with narrowly rounded ends, smooth, (9.3 –) 10–11 (– 12) × 3.7–4.7 µm (M = 10.6 × 4.2 µm, N = 40), with straight germ slit nearly the full length of the spore on the flattened side, a hyaline sheath visible in 1 % SDS, swollen at both ends, forming non-cellular appendages.

Remarks.

Xylaria acifer clusters with X. hedyosmicola in the phylogenetic tree, and they share some similarities in stromatal morphology, yet they also exhibit distinct differences. The stromata of X. hedyosmicola possess more prominent perithecial mounds (half-exposed to fully exposed), and its ascospores are brown, ellipsoid, and larger (( 12 –) 13–15 (– 16.7) × (6 –) 6.5–7.5 (– 8.5) µm) ( Pan et al. 2022). Xylaria vittatipiliformis Y. - M. Ju, H. - M. Hsieh & Fournier and X. vittiformis Y. - M. Ju & H. - M. Hsieh are morphologically similar to X. acifer . Xylaria vittatipiliformis can be distinguished by its band-like striped grayish brown outer peeling layer and larger ascospores (( 10 –) 11–12 (– 12.5) × (5.5 –) 6–7 (– 7.5) µm) ( Ju and Hsieh 2023). Xylaria vittiformis is separated from X. acifer by its grayish brown outer peeling layer split into band-like stripes, smaller perithecia (150–200 μm broad), and ellipsoid ascospores, (8 –) 8.5–10 (– 11) × (4 –) 4.5–5 (– 5.5) µm ( Ju and Hsieh 2023).

Xylaria appendiculatoides Y. M. Ju & H. M. Hsieh , X. filiformis , and X. simplicissima are also similar to X. acifer in stromatal morphology but are distinctly different. Xylaria appendiculatoides has stromata with sharper ostioles (conic-papillate, tilting upwards) and larger ascospores (( 14 –) 15–16 (– 17) × (6.5 –) 7.0–7.5 (– 8) µm) ( Ju and Hsieh 2023). Xylaria filiformis and X. simplicissima have ascospores that are markedly different from those of X. acifer . Xylaria filiformis has light brown ascospores that are larger (( 9.5 –) 11.5–13.5 (– 14.5) × (4 –) 4.5–5.5 (– 6) µm) ( Ju and Hsieh 2023). Xylaria simplicissima has larger ascospores (( 15 –) 16.5–19 (– 21.5) × (5 –) 5.5–6.5 (– 7.5) µm) that lack non-cellular appendages ( Ju and Hsieh 2023). Additionally, X. acifer , X. filiformis , and X. simplicissima are distributed in different clades in the phylogenetic tree. Xylaria maitlandii (Dennis) D. Hawksw. has a somewhat similar stromatal shape to X. acifer . However, X. maitlandii has hairy stromata, which clearly distinguishes it from X. acifer ( Ju and Hsieh 2023).

Additional specimen examined.

China • Hainan Province, Diaoluoshan Area of Hainan Tropical Rainforest National Park ; 18°43'31"N, 109°52'14"E; elevation 937 m; on fallen leaves, 18 June 2023, Xiaoyan Pan ( HAFFR 130 ). GenBank accession numbers PQ 483150 (ITS) and PQ 498328 ( RPB 2 ) .

Figures

Figure 2. Xylaria acifer (HAFFR 122) a stromata on leaves b stromatal surface and ostioles (arrow) c section through stroma, showing perithecia d ascus in Melzer’s reagent e, f ascospore showing non-cellular appendages in 1 % SDS (arrows) g, h ascal apical ring in Melzer’s reagent i ascospores in Melzer’s reagent j ascus in water k ascospore showing a nearly spore-length straight germ slit in Melzer’s reagent l ascospore under SEM. Scale bars: 1 cm (a); 200 µm (b, c); 10 µm (d – k); 5 µm (l).