Xylaria cubensis (Mont.) Fr.

Wu, You-Peng, Pi, Yin-Hui, Long, Si-Han, Liu, Li-Li, Zhang, Xu, Long, Qing-De, Lin, Yan, Kang, Ying-Qian, Kang, Ji-Chuan, Wijayawardene, Nalin N. & Li, Qi-Rui, 2022, Morphology and phylogeny reveal two novel Xylaria (Xylariaceae) species from China, Phytotaxa 550 (2), pp. 130-146 : 137

Xylaria cubensis (Mont.) Fr. , Nova Acta Regia Soc. Sci. Upsal. (Ser. 3) 1: 126. 1851; sensu Rogers (1984) ( Fig. 3 )

Synonymy:

Hypoxylon cubense Mont., Annls Sci. Nat., Bot. , sér. 2 13: 345 (1840)

MycoBank number: MB 179243

Saprobic on dead tree trunk, forming on the host surface. Sexual morph: Stromata solitary, cylindric-clavate, usually unbranched, 2.2–5.8 cm long × 0.6–1.2. cm broad (x = 3.6 × 0.8 cm, n = 10), with short or long stipe from a pannose base, externally copper brown to brownish-black, internally white. Surface smooth to slightly rough with fine cracks. Perithecia ovoid, 0.4–0.8 mm diam., ostioles inconspicuous to conspicuous, prominent. Ostioles papillae. Asci 107– 162 × 5.3‒8.2 μm (x = 124 × 6.8 μm, n = 30), unitunicate, 8-spored, cylindrical, long-stipitate, apically rounded, with a J+, rectangular, apical ring, blue staining in Melzer’s reagent, 1.5–2.5 μm (x = 2.2 μm, n = 30) high, 1.5–2 μm (x = 1.8 μm, n = 30) wide. Ascospores 8–9.5 × 4–5 μm (x = 8.5 × 4.5 μm, n = 30), brown to dark brown, unicellular, ellipsoid-inequilateral, with widely rounded ends, smooth, with a straight central germ slit along much less than sporelength, lacking appendages and sheaths. Asexual morph: Undetermined.

Specimens examined: CHINA, Hainan Province, Haikou City, Huoshankou Geological Park (19.554365°N, 110.13203°E), elev. 152 m, on dead wood of unknown plant roots, November 2020, Youpeng Wu and Lili Liu, 2020HSK4 (GMB0075, KUN-HKAS 122631; living culture GMBC 0075).

Culture characteristics: Colonies on OA reaching 4–5 mm diam. after 2 weeks at 25 °C. White at first, with regular margins, then with a peripheral ring-shaped extension spreading toward the edge of the Petri dish; reverse milky white in the center, light white marginal area. After 4 weeks, colonies on OA reaching 9 cm, stromata arising from concentric zones, cylindrical, tapering upwards, flexuous, unbranched; reverse light grey, emerge black dots. No conidia were observed.

Notes: Xylaria cubensis is a common species and was reported from Africa, North and South America, Asia, Oceania and China (Ma et al. 2012). Xylaria cubensis is mainly characterized by its smooth surface with papillate ostioles, copper-colored, brown or brownish-black clavate stromata with rounded fertile apices and small ascospores mostly with unclear germ slit ( Rogers 1984), which has been reported from Taiwan ( Ju et al. 1999) and Guizhou, Jilin, Yunnan provinces in China (Ma et al. 2012). Our specimens examined in this study display the same characters of X. cubensis described by Rogers (1984) and Ma et al. (2012), such as long stipe from a pannose base, with papillate ostioles of stromata surface, externally copper brown to brownish-black, internally white; ascospores with unclear germ slit less than spore-length, lacking appendages and sheaths. Phylogenetic analyses of a combined alignment of β-tubulin, rpb 2 and α-actin genes showed that the strain GMB0075 grouped with X. cubensis (HAST 515) with high statistical support (100% ML, 1.00 BYPP; Fig. 1 ). This is the first record of X. cubensis from Hainan province, China.

Figures

FIGURE 1. RAxML tree based on analysis of a combined dataset of β-tubulin, rpb2 and α-actin sequence dataset from selected species of Xylariales. Bootstrap support values for maximum likelihood (ML) greater than 50%, and Bayesian posterior probabilities (BYPP) greater than 0.90 are given at the nodes. Strain numbers are noted after the species names. Ex-type strains are in bold. Newly generated taxa are in red. The tree is rooted to the outgroup of Camillea obularia (ATCC 28093).

FIGURE 3. Xylaria cubensis (GMB0075). A. Stromata on the surface of host. B. Stroma. C. Close-up of stroma. D. Transverse section of stroma. E. Longitudinal section of stroma. F. Culture on OA from above and below. G–I.Asci with ascospores. J. Ascus apex with a J+, apical ring (stained in Melzer’s reagent). K–M. Ascospores. N. Ascospores with indehiscent perispore in 10% KOH. Scale bars: B = 500 μm, C = 200 μm, D, E = 150 μm, G–N = 10 μm.