Hydnotrya zayuensis L. Li & S.H. Li, sp. nov. Plate 2 Diagnosis. Differs from all other species in Hydnotrya by its almost single-chambered ascomata, light golden yellow ellipsoidal ascospores. Etomology. zayuensis from Latin, referring to the type locality. Holotype. China, Tibet, Zayu (28°35.00'N, 98°06.00'E), alt. 3770 m, in a forest of Abies sp., 11 August 2022, Lin Li BMDLU L22027. Description. Ascomata irregularly globose, 1.5-2.5cm in diameter when fresh, smooth, convoluted, almost single-chambered with a primary apical opening, sometimes the opening nearly closed like a seam, white fluffy inside, surface cinnamon (5E8); shrunken, becoming fuzzy when dried, although there are no protruding hyphae cells from the outermost layer of the peridium. Elastic to crisp. No special smell was noticed. Peridium two-layered, 180-250 µm thick, outer layer 40-80 µm thick, composed of ellipsoid or irregular cells, which grow larger toward the surface, with a yellow brown (4C5) pigment deposited on the outermost cells; inner layer, 110-160 µm thick, consisting of hyaline parallel interwoven hyphae. Gleba chamber hollow, lined with off-white (1A2) hymenium when immature; two-layered when mature, the outer layer golden brown (5C7), the inner layer yellowish to whitish (4A2), hymenial surface fluffy. Asci cylindrical, 118.5-130.5 × 15.0-22.5 µm, 8-spored, thin-walled, narrowed into a long stalk (20-40 μm) at the base, without croziers, arranged in a palisade. Ascospore strictly uniseriate, ellipsoid (shape including the thickened exosporium), (17-)20-30.5 × 15.5-18.0 μm, Q = 1.5 ± 0.16, hyaline, exosporium thin when immature, surface roughness, and looks crumbly, golden yellow (4B8) when mature. Paraphyses hyaline, straight stick shape, 1.5-2.5 µm in diam, septate, apical slightly inflated, exceeding the asci by 120-160 µm. Ecology and distribution. Hypogeous, solitary in the humus under Abies sp. mixed with shrubs of Rhododendron spp. Fruiting in summer, from July to September. Known only from Zayu, Tibet, China. Additional specimen examined. China, Tibet, Zayu, 28°47.00'N, 98°21.00'E, alt. 3840 m, in a forest of Abies sp., 15.July.2022, Shucheng He (BMDLU L22024. GenBank: ITS = OP908304, LSU = OP908301). Notes. Morphologically, H. zayuensis is similar to H. laojunshanensis. However, H. zayuensis has much smaller ascospores, and a thinner peridium, as well as lighter colored ascomata. Molecular analysis showed that H. zayuensis is distinct from H. laojunshanensis and other species of Hydnotrya.

Published as part of Li, Lin, Wan, Shan-Ping, Wang, Yun, Thongklang, Naritsada, Tang, Song-Ming, Luo, Zong-Long & Li, Shu-Hong, 2023, New species of Hydnotrya (Ascomycota, Pezizomycetes) from southwestern China with notes on morphological characteristics of 17 species of Hydnotrya, pp. 49-67 in MycoKeys 100 on page 49, DOI: 10.3897/mycokeys.100.106709