Xylaria microcarpa Hai X. Ma & Yu Li sp. nov. Fig. 3 Type. China. Yunnan Province, Xishuangbanna Prefecture, Dadugang Town, Guanping Village, on legume pods, 21 January 2015, Haixia Ma, FCATAS 883 (Col. 233). Etymology. Microcarpa (Lat.): referring to its stroma that it is very small. Teleomorph. Stromata upright or prostrate, often densely gregarious in large groups, unbranched, cylindrical to filiform, with acute sterile apices, on tomentose stipes, 3.5–9 mm total height; fertile parts 2–6 mm high × 0.6–1.5 mm broad, filiform to cylindrical, brown tomentose dense or sparse, nodulose with perithecial contours exposed; stipes 1.5–4 mm high × 0.3–0.5 mm broad, terete, with conspicuously dark brown tomentose, arising from slighly enlarged base; surface black, interior light yellow, solid, woody. Perithecia subglobose, 300–500 µm. Ostioles conic-papillate. Asci eight-spored arranged in uniseriate manner, cylindrical, long-stipitate, (96 –) 105–125 (– 140) µm total length, the spore-bearing parts (56 –) 60–70 (– 75) µm long × (6.0 –) 6.4–7.1 (– 7.6) µm broad, the stipes 30–56 µm long, with apical ring bluing in Melzer’s reagent, tubular or urn-shaped, 1.5–2.5 (– 2.9) µm high × 1.4–1.8 µm diam. Ascospores light brown, unicellular, ellipsoid-inequilateral, with narrowly rounded ends, sometimes with pinched on one end, smooth, (9.5 –) 10–11 (– 11.5) × (4.5 –) 5–6 (– 6.2) µm (M = 10.5 × 5.5 µm, Q = 1.9, n = 60 / 2), with a inconspicuous straight germ slit almost spore-length, lacking a sheath or appendages visible in india ink or 1 % SDS. Additional specimen examined. China. Yunnan Province, Xishuangbanna Prefecture, Xishuangbanna Tropical Botanical Garden, on legume pods, 20 January 2015, Haixia Ma, FCATAS 885 (Col. 239). Notes. Xylaria microcarpa is characterized by very small stromata growing in groups, overlain with a dark brown tomentum, ascospores light brown with an inconspicuous straight germ slit, lacking a sheath or appendages, and grows on leguminous pods. The new species resembles X. fabacearum R. H. Perera, E. B. G. Jones & K. D. Hyde by sharing small stromata and ascospores length dimensions, but differs from the latter species in having stromata branched sometimes, stromatal surface without tomentose, brown to dark brown ascospores with conspicuous straight germ slit (Perera et al. 2020). Xylaria luzonensis on Bauhinia cumingiana (Fabaceae) differs from X. microcarpa by having branched and larger stromata, smaller perithecia, and smaller ascospores (8 –) 8.5–9.5 (– 10) × 3–3.5 (– 4) µm (M = 8.9 × 3.4 µm) (Ju et al. 2018). Xylaria microcarpa is somewhat similar to X. ianthinovelutina and X. culleniae in stromatal surface with tomentum and grow on leguminous pods, but the later two taxa differ in larger stromata, ascospores with a straight germ slit slightly less than spore-length, surrounded with a hyaline sheath and non-cellular appendages (Ju et al. 2018). The phylogenetic tree showed that Xylaria microcarpa and X. aethiopica J. Fourn., Y. M. Ju, H. M. Hsieh & U. Lindem are sister taxa with a strong supported branch in BI tree (BS = 0.98), but X. aethiopica is distinct morphologically with larger stromata 15–30 mm total height, brown to dark brown and slightly larger ascospores (9.7 –) 11–13 (– 13.5) × (3.5 –) 3.8–4.5 (– 4.9) µm (M = 11.9 × 4.1 µm) with a conspicuous straight germ and appendages, and grows on fallen woody pods of Millettia ferruginea (Fabaceae) (Fournier et al. 2018 b).

Published as part of Zhu, An-Hong, Song, Zi-Kun, Wang, Jun-Fang, Guan, Hao-Wen, Qu, Zhi & Ma, Hai-Xia, 2024, Multi-gene phylogenetic and taxonomic contributions to Xylaria (Ascomycota) associated with fallen fruits from China, pp. 23-41 in MycoKeys 106 on pages 23-41, DOI: 10.3897/mycokeys.106.124944