Xylaria acericola H.X. Ma, Lar. N. Vasilyeva & Yu Li, 2020

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 : 37-39

Xylaria acericola H.X. Ma, Lar. N. Vasilyeva & Yu Li , sp. nov. ( Figs. 1 , 2 )

Mycobank: MB 833364 Etymology:— acericola (Lat.) : referring to the host where the fungus inhabits. Holotype:— CHINA. Jilin Province, Yanbian Korea Autonomous Prefecture, Helong City , Huanggou Forest Farm , 42°41′N & 128°62′E,

alt. 740 m, on bark of Acer sp. in temperate coniferous and broad-leaved mixed forest, 28 Aug 2014, Col. 177, H.-X. Ma

(FCATAS838).

Teleomorph:—Stromata erumpent through the bark singly or in groups, pulvinate or peltate, flat-topped, with irregular margins, 2–7 mm diam, 1.5–3 mm thick, often gregarious and coherent together, attached to the substrate on a narrow central connective or a short stipe; surface cinnamon brown to dark brown, with conspicuous cracked, mostly longitudinally, with slight perithecial contours; texture soft; interior white, solid, woody. Perithecia ovoid, 0.6–0.7 mm high× 0.5–0.6 mm diam. Ostioles black, slightly papillate. Asci with eight ascospores obliquely arranged in uniseriate manner, cylindrical, long-stipitate, (140–)155–165(–185) µm total length, the spore-bearing part (95–)105–114(–120) µm long × (9–) 9.5–10.5(–11.5) µm diam., the stipes 30–60 µm long, with apical ring bluing in Melzer’s iodine reagent, urn-shaped, 5.0–6.8 µm high × 3.5–4.7 µm diam. Ascospores brown, dark-brown to black, unicellular, ellipsoid or fusiform, inequilateral, with narrowly rounded ends, occasionally minutely pinched on one end, smooth, (19.0–)20.5– 22.0(–23.6) ×(7.6–)8.5–9.5(–10.5) µm(M = 20.9 × 9.1 μm, n = 30),with a conspicuous spiralling germ slit less than spore-length; no sheath or appendages visible in India ink.

Additional specimens examined: — CHINA. Jilin Province, Changbai Mountain Natural Reserve, Hanconggou, 42°25′N & 128°12′E, alt. 760 m, on bark of Acer sp. in the temperate coniferous and broad-leaved mixed forest, 27 Aug 2014, Col.183, H.-X.Ma (FCATAS839).

Remarks:— Xylaria acericola is a member of penzigioid Xylaria group, which is characterized by having small, subsessile stromata attached to the substrate by a narrow connective ( Rawla & Narula 1983, Ju et al. 2012). Fournier (2014) described a species, named “ Rosellinia ” callosa Winter from France, which has a similar stromatal gross morphology. The fungus is on the collar of a small dead trunk of Acer campestre , and has longer (23.2–28.4 µm vs. 20.5–22.0 µm), thinner(6.5–7.9 µm vs. 8.5–9.5 µm), fusiform to navicular ascospores (Me = 25.5 × 7.2 µm vs. 20.9 × 9.1 μm), and with an oblique, straight to slightly sigmoid germ slit, while the Chinese collections are on the bark of living tree of Acer sp. , and has shorter, wider, ellipsoid or fusiform ascospores with a spiral germ slit. Unfortunately, DNA sequences of the France material are not available.

Morphologically, X. acericola is similar to Xylaria lechatii Y.M. Ju, H.M. Hsieh, J.D. Rogers & J. Fournier , but the latter has smaller ascospores (12–15 × 6.5–8 µm)with a straight, spore-length germ slit, smaller perithecia (0.3–0.4 mm diam × 0.4–0.5 mm high), and smaller ascus apical ring (3 µm high and 4 µm broad), and occurring in French West Indies ( Ju et al. 2012). The molecular phylogeny did not reveal any contradictions in relation to the morphological data ( Ju et al. 2012).

Figures

FIGURE 1. Xylaira acericola(FCATAS838, Holotype).A,C. Stromatal habit. B. Close-up view of stromatal surface, showing perithecial mounds and ostiolar disks. D. Section through stroma, showing perithecia. Scale is indicated by bars (A = 2 mm; B,D = 0.5 mm; C = 1mm).

FIGURE 2. Xylaira acericola (FCATAS838, Holotype). A,B. Asci in water. C. Ascospores in water. D,E. Ascus apical ring in Melzer’s reagent. F–I. Ascospore with germ slit. Scale is indicated by bars (A= 20 µm; B–I = 10 µm).