The genus Clavariadelphus (Clavariadelphaceae, Gomphales) in China Author Huang, Hong-Yan School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, 650500, China Author Zhao, Jie School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, 650500, China Author Zhang, Ping College of Life Science, Hunan Normal University, Changsha, 410081, China Author Ge, Zai-Wei Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China https://orcid.org/0000-0003-3184-4604 Author Li, Xian School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, 650500, China xianlikm@163.com Author Tang, Li-Ping School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, 650500, China lipingtang11@qq.com text MycoKeys 2020 70 89 121 http://dx.doi.org/10.3897/mycokeys.70.54149 journal article http://dx.doi.org/10.3897/mycokeys.70.54149 1314-4049-70-89 65FFE6B3A0F25CEF8D1B84BCEB9F6D24 4. Clavariadelphus gansuensis J. Zhao & L.P. Tang sp. nov. Figs 2f , 3d , 4d , 5d , 9a, b Diagnosis. This species is characterised by its orange, clavate basidiomes with slightly enlarged, truncate, sterile apex, broadly ellipsoid to ellipsoid basidiospores, hyphae of the basal mycelium with nipple-shaped protuberances and prism-like crystals and basidiomes that turn pink or light cherry-red in KOH. It differs from C. truncatus by the latter's robust, darker basidiomes with enlarged apices, and larger basidiospores. Figure 9. Microscopic features of Clavariadelphus gansuensis (HKAS 76487, holotype). a Leptocystidia and immature basidia b Basidia. Etymology. Latin " gansuensis " refers to the holotype location in Gansu Province. Description. Basidiomes up to 9 cm high, enlarged upwards to 1.6 cm diam., simple, clavate; hymenium longitudinally rugose, pruinose, light yellow to greyish-orange at maturity; apex initially obtuse or broadly rounded, flattening laterally, then truncate, slightly rugose, light orange or melon-orange (5A5-7) to orange (6A6-7) in age; base terete, smooth, pruinose, dirty white or pallid where covered, otherwise pruinose, pale orange or light orange (5A3-4); mycelial hyphae white; flesh initially solid, then soft and spongy upwards as the apex enlarges, white to pallid. Odour and taste not recorded. Hymenium limited to the side of basidiomata, composed of basidia and leptocystidia; the apex of basidiomata composed of sterile elements 15-25 x 5-7 μm , clavate, thin-walled, smooth, clamped. Basidia 75-90 x 8-10 μm , clavate, hyaline, thin-walled to thick-walled, 4-spored, sterigmata 7-10 μm in length. Basidiospores [20/1/1] 8.3-10.1 (-10.3) x 5.3-6.3 (-6.4) μm , Q = (1.34-) 1.47 -1.78 (-1.83), Q m = 1.60 +/- 0.09, ellipsoid to broadly ellipsoid, ovate or amygdaliform, with a small apiculus, inamyloid, thin-walled, hyaline in KOH. Leptocystidia 50-65 x 3-5 μm , scattered amongst and scarcely projecting beyond the basidia, cylindrical to narrowly clavate, thin-walled, smooth, hyaline, non-pigmented, clamped, inflated apically at maturity, at times with apical or sub-apical branches. Mycelial hyphae 2-3 μm diam., interwoven or aggregated into rhizomorphic strands, branched, clamped; the hyphal walls echinulate with light microscopy, covered with massive nipple-shaped protuberances, as well as encrusted with prism-like crystals up 5 μm long that are insoluble in KOH. Chemical reactions. (dried basidiomes): KOH = positive, pink, light coral or light cherry-red; FeCl3 = positive, green-yellow; NH4OH = positive, golden-rod or vivid yellow; phenol = positive, yellow; ethanol, FeSO4 and Melzer's reagent = negative. Known distribution and ecology. NW China, Gansu Province. Solitary on the ground in coniferous woods ( Abies spp.) or mixed with broad-leaved trees ( Betula spp. and Rosaceae ) at elevations of approximately 3000 m. Materials examined. China. Gansu Province: Lintan Prefecture, Yeliguan National Forest Park, coniferous woods ( Abies spp.) or mixed with Betula spp. and Rosaceae plants, alt. 3000 m, 10 August 2012, X.T. Zhu 638 (HKAS 76487, Holotype ); Wudu Prefecture, September 1992, M.L. Tian M6465 (HMAS 63052). Comments. Clavariadelphus gansuensis , currently known only from NW China, is distinct by its slender, clavate, orange basidiomes with truncate apex, ellipsoid basidiospores (8.3-10.1 x 5.3-6.3 μm ), pink staining reaction to KOH, hyphae of the basal mycelium with nipple-shaped protuberances and prism-like crystals and solitary growth habit in coniferous or mixed forests. This species is most likely to be confused with several taxa, including C. amplus , C. pallido-incarnatus , C. pakistanicus , C. truncatus and C. unicolor . The comparison between C. gansuensis and C. amplus can be found in our treatment of C. amplus . According to our phylogenetic analyses, C. gansuensis is allied with the sequence of " C. truncatus " from GenBank with strong support (Fig. 1 ).