Xylaria sibirica Y.M. Ju, H.M. Hsieh, Lar.N. Vassiljeva & Akulov, Mycologia

Ma, Hai-Xia, Qu, Zhi, Peng, Mingkai & Li, Yu, 2020, Two penzigioid Xylaria species described from China based on morphological and molecular characters, Phytotaxa 436 (1), pp. 36-44 : 39-40

Xylaria sibirica Y.M. Ju, H.M. Hsieh, Lar.N. Vassiljeva & Akulov, Mycologia 101(4): 551.2009. ( Figs.3 , 4 )

Teleomorph. −Stromata solitary or gregarious, discoid or pulvinate, flat-topped, 1–6 mm diam, 0.5–1 mm thick, attached to the substrate on a narrow central connective, with perithecial mounds; surface dark brown, with distinctly conspicuous whitish texture on younger stromata; interior white, woody; texture soft. Perithecia ovoid, 0.3–0.4 mm high × 0.4–0.6 mm diam. Ostioles black, papillate. Asci with eight ascospores obliquely arranged in uniseriate manner, occasionally in biseriate manner, cylindrical, long-stipitate, (160–)175–190(–215) µm total length, the spore-bearing part (72–)82–120(–130) µm long ×10–11.5 µm diam., the stipes 60–90 µm long, with apical ring bluing in Melzer’s iodine reagent, tubular to inverted hat-shaped, 2.5–4.5 µm high × 3–5 µm diam. Ascospores brown to dark-brown, unicellular, ellipsoid, equilateral or nearly equilateral, with narrowly or broadly rounded ends, smooth, (13.0–)14.5– 16.5(–18.5) ×(6.5–)7–9(–10) µm(M = 15.5 × 9.2 μm, n = 30),with a conspicuous sigmoid germ slit less than spore-length; no sheath or appendages visible in India ink.

Specimen examined: — CHINA. Sichuan Province,Ganzi Tibetan Autonomous Region, Daocheng County, Yading Natural Reserve, 28°21′N & 100°9′E, alt. 3500 m, on rotten wood in the subalpine coniferous forest, 5 Sep 2015, Col. Q9, H.-X. Ma (FCATAS764).

Remarks:— Xylaria sibirica was originally described by Ju et al. (2009) on branches from Russian Far East. This species was reported by Vasilyeva (1998) as Hypoxylon enteroleucum (Speg.) P. Martin. However , H. enteroleucum differs from X. sibirica in having light brown, narvicular ascospores and widely diffused stromata. The Chinese collection matches well the description in Ju et al. (2009) in morphology, and the phylogenetic analyses of ITS rDNA and β-tubulin sequences confirm that it is conspecific with X. sibirica ( Ju et al. 2009) . Phylogenetically, X. sibirica is closely related to X. lechatii judging from the available data ( Ju et al. 2012). However, X. lechatii can be distinguished by its slightly smaller ascospores (12–15 × 6.5–8 µm) with a straight spore-length germ slit.

Figures

FIGURE 3. Xylaira sibirica (FCATAS764).A,B. Stromatal habit. C. Close-up view of stromatal surface, showing perithecial mounds and ostiolar disks. D. Section through stroma, showing perithecia. Scale is indicated by bars (A = 1 mm; B,D = 0.5 mm; C = 0.2mm).

FIGURE 4. Xylaira sibirica (FCATAS764).A.Ascus in Melzer’s reagent. B. Ascus in water. C.Ascospores in water. D.Ascus apical ring in Melzer’s reagent. E,F. Ascospore with germ slit. G. Ascospore. Scale is indicated by bars (A,C,D = 10 µm; B,E–G = 5 µm).