Morphology and phylogeny of Cytospora (Cytosporaceae, Diaporthales) species associated with plant cankers in Tibet, China Author Li, Jiangrong https://orcid.org/0000-0002-6679-5227 Key Laboratory of Forest Ecology in Tibet Plateau, Ministry of Education, Institute of Tibet Plateau Ecology, Tibet Agricultual & Animal Husbandry University, Nyingchi, Tibet 860000, China & National Key Station of Field Scientific Observation & Experiment, Nyingchi, Tibet 860000, China Author Li, Jieting https://orcid.org/0009-0001-8984-7261 Key Laboratory of Forest Ecology in Tibet Plateau, Ministry of Education, Institute of Tibet Plateau Ecology, Tibet Agricultual & Animal Husbandry University, Nyingchi, Tibet 860000, China & National Key Station of Field Scientific Observation & Experiment, Nyingchi, Tibet 860000, China Author Jiang, Ning https://orcid.org/0000-0002-9656-8500 Key Laboratory of Biodiversity Conservation of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China n.jiang@caf.ac.cn text MycoKeys 2024 2024-04-16 104 51 70 http://dx.doi.org/10.3897/mycokeys.104.113567 journal article http://dx.doi.org/10.3897/mycokeys.104.113567 1314-4049-104-51 B1D7E4C126FF5EB78C4F0AB13FF43CDF Cytospora sibiraeicola Ning Jiang sp. nov. Fig. 4 Etymology. " sibiraei " refers to the host genus Sibiraea and "- cola " means inhabiting. Holotype. CAF800084. Description. Associated with branch canker disease of Sibiraea angustata . Sexual morph : Undetermined. Asexual morph : Pycnidial stromata ostiolated, immersed or semi-immersed in the host bark, scattered, discoid, with multiple locules. Conceptacle black, circular surrounded stromata. Ectostromatic disc black, circular to ovoid, (200-)300-450(-500) μm diam., with one ostiole per disc. Ostioles dark, at the same level as the disc, (30-)60-80(-95) μm diam. Locule numerous, arranged circularly or elliptically with independent walls, (200-)250-380(-500) μm diam. Peridium comprising few layers of cells of textura angularis, with innermost layer brown, outer layer brown to dark brown. Conidiophores hyaline, unbranched, thin-walled, filamentous. Conidiogenous cells enteroblastic polyphialidic, 12.5-32.5 x 2-3.5 μm . Conidia hyaline, allantoid, smooth, aseptate, thin-walled, (3.3-)3.4-4.3(-4.5) x 1.2-1.6 μm (x̄ = 3.9 x 1.5 μm ). Figure 4. Cytospora sibiraeicola (CAF800084, holotype) A, B canker disease symptom C conidioma D transverse section through a conidioma E longitudinal section through a conidioma F conidiophores and conidia G, H conidia. Scale bars: 2000 µm ( B ); 1000 µm ( C-E ); 10 µm ( F-H ). Culture characteristics. Colonies on PDA flat, with flocculent aerial mycelium and undulate margin, initially white, becoming olivaceous grey and reaching 90 mm diameter after 10 days at 25 °C, sterile. Materials examined. China , Tibet Tibetan Autonomous Region , Lhasa City , Mozhugongka County , Riduo Township , Zen Village , on cankered branches of Sibiraea angustata , 28 July 2022 , Jin Peng, Liu Yuanyuan, Jiang Ning and Liu Min (CAF800083, holotype ); ex-type cultures CFCC 59100 and CFCC 59101 . Notes. Cytospora sibiraeicola is phylogenetically close to C. phialidica and C. viticola (Fig. 1 ). Morphologically, C. sibiraeicola (3.4-4.3 x 1.2-1.6 μm ) and C. phialidica (3.5-5 x 1-2 μm ) have much shorter conidia than C. viticola (5.2-7 x 0.9-1.6 μm ) ( Lawrence et al. 2017 ; Li et al. 2020 ). In addition, these three species can be distinguished by the host and distribution ( C. sibiraeicola from Sibiraea angustata in China vs. C. phialidica from Alnus glutinosa in Italy vs. C. viticola from Vitis vinifera in the USA) ( Lawrence et al. 2017 ; Li et al. 2020 ).