Hypoxylon jianfengense Hai X. Ma

Song, Zikun, Pan, Xiaoyan, Li, Changtian, Ma, Hai-Xia & Li, Yu, 2022, Two new species of Hypoxylon (Hypoxylaceae) from China based on morphological and DNA sequence data analyses, Phytotaxa 538 (3), pp. 213-224 : 220-221

Hypoxylon jianfengense Hai X. Ma & Z. K. Song, sp.nov. ( Fig. 3 )

MycoBank: MB839550, Facesoffungi number: FoF 09870.

Etymology:— In reference to the locality where the species was collected.

Holotype: — CHINA. Hainan Province, Jianfengling National Natural Reserve, Mingfeng Valley , saprobic on decaying wood, 23 October 2020, Haixia Ma (FCATAS 845).

Sexual state: — Stromata pulvinate to effused-pulvinate, continuous, with inconspicuous or slightly conspicuous perithecial mounds, 0.1–0.2 cm thick; surface Dark Brick (60), Livid Vinaceous (83) and Brown Vinaceous (84); yellowish-brown granules immediately beneath surface and between perithecia; yielding Dark Green (21), Isabelline (65) and Dull Green (70) pigments in 10% KOH; tissue below the perithecial layer inconspicuous, brown to black, woody to carbonaceous, 0.2–0.5 mm thick. Perithecia tubular to long tubular or obovoid, black, 0.2–0.3 mm broad × 0.6–0.9 mm high. Ostioles umbilicate, encircled with black areas 87–198 µm diam on stromatal surface, opening lower than stromatal surface. Asci cylindrical, with eight uniseriate ascospores, 69–161 µm total length × 5.5–7.7 µm broad, the spore-bearing portion 60–83 µm long and stipes (5–) 12–82 µm long, with amyloid and discoid apical apparatus bluing in Melzer’s reagent, 0.7–1.2 µm high × 1.8–2.4 µm broad. Ascospores smooth, light brown to dark brown, unicellular, inequilateral ellipsoid, with narrowly rounded ends, 10.3–13.6 × (4.2–) 4.7–6.1 µm (n=39, M=12.1 × 5.5 µm), with conspicuous straight germ slit spore-length on the convex side; perispore dehiscent in 10% KOH, with conspicuous coil-like ornamentation in SEM; epispore smooth. Asexual state:— Undetermined.

Additional specimens examined: — CHINA. Hainan Province, Jianfengling National Natural Reserve, Mingfeng Valley , on decaying wood, 23 October 2020, Hai X. Ma (FCATAS 847) .

Note: —Despite the strong statistical support reflected on the phylogenetic relationships with H. invadens J. Fourn. , this species exhibits conspicuous distinction in the teleomorph. The most striking feature of H. invadens is that its stromata grow on aborted primordia of Hypoxylon fragiforme (Pers.: Fr.) J. Kickx f. to form hemispherical stromata. In addition, H. jianfengense can be distinguished from H. invadens easily by its pulvinate to effused-pulvinate stromata and tubular to long tubular perithecia, while the latter has glomerate stromata and subglobose to obovoid perithecia ( Fournier 2014). Furthermore, the first non-volatile secondary metabolites were isolated from H. invadens ( Becker et al. 2020) and these seems to be a strong chemotaxonomic marker to separate other species. Morphologically, H. jianfenense resembles H. trugodes in obovoid, tubular, to long tubular perithecia. However, the latter differs by Pure yellow (14) or Amber (47) pigments extracted in the 10% KOH, smaller size of apical apparatus (0.3–0.8 µm high × 1.5–2 µm broad) and ascospores (8–11 × 3.5–4.5 µm) ( Ju & Rogers 1996).

Figures

FIGURE 3. Hypoxylon jianfengense (Holotype FACATAS 845). A. Stromata on wood. B. Stromatal surface and ostioles. C, D. Stroma in vertical section showing the perithecia and tissue below the perithecial layer. E. KOH-extractable pigments. F. Stromatal granules in water. G. Mature and immature asci in water. H. Asci in Melzer’s reagent. I. Immature asci in water. J, K. Mature asci in water. L. Apical apparatus in Melzer’ s reagent. M. Ascospore in water showing germ slit. N. Ascospores in water. O. Ascospores in 10% KOH. P. Ascospore under SEM. Bars: A = 5 mm; B = 0.3 mm; C = 0.5 mm; D = 0.1 mm; G, I–K = 20 µm; H, L–O = 10 µm; P = 2.5 µm.