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 myricicola Ning Jiang sp. nov. Fig. 2 Etymology. " myrici " refers to the host genus Myricaria and "- cola " means inhabiting. Figure 2. Cytospora myricicola (CAF800083, 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, D ); 500 µm ( E ); 10 µm ( F-H ). Holotype. CAF800083. Description. Associated with branch canker disease of Myricaria paniculate . Sexual morph : Undetermined. Asexual morph : Pycnidial stromata ostiolated, semi-immersed in the host bark, scattered, discoid, with multiple locules. Conceptacle dark brown to black, circular surrounded stromata. Ectostromatic disc dark yellow, circular to ovoid, (250-)350-450(-550) μm diam., with one ostiole per disc. Ostioles dark, at the same level as the disc, (35-)55-85(-100) μm diam. Locule numerous, arranged circularly or elliptically with independent walls (245-)300-450(-550) μm diam. Peridium comprising a few layers of cells of textura angularis, with innermost layer brown, outer layer brown to dark brown. Conidiophores hyaline, branched, thin-walled, filamentous. Conidiogenous cells enteroblastic polyphialidic, 6.5-35.5 x 1.5-2.5 μm . Conidia hyaline, allantoid, smooth, aseptate, thin-walled, (4.4-)4.7-5.6(-5.8) x 1.4-1.7 μm (x̄ = 5.2 x 1.6 μm ). Culture characteristics. Colonies on PDA flat, with flocculent aerial mycelium and entire edge, initially white, becoming dark 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 Myricaria paniculate , 28 July 2022 , Jin Peng, Liu Yuanyuan, Jiang Ning and Liu Min (CAF800083, holotype ); ex-type culture CFCC 59323 . China , Tibet Tibetan Autonomous Region , Lhasa City , Mozhugongka County , Riduo Township , Renqinglin Village , on cankered branches of Myricaria paniculate , 28 July 2022 , Jin Peng, Liu Yuanyuan, Jiang Ning and Liu Min (XZ010B); cultures CFCC 59324 and CFCC 59325 . Notes. Phylogenetically, Cytospora myricicola is close to C. fraxinigena , C. junipericola , C. pubescentis , C. quercicola and C. rosae (Fig. 1 ). Of these six species, only C. myricicola , C. pubescentis and C. rosae have asexual morph descriptions; C. myricicola (4.7-5.6 x 1.4-1.7 μm ) is different from C. pubescentis (5.8-7.5 x 1.3-1.6 μm ) by shorter conidia and from C. rosae (3-5 x 0.5-1 μm ) by larger conidia ( Senanayake et al. 2017 ; Shang et al. 2020 ). In addition, C. myricicola can be distinguished from the other five species by host and distribution ( C. myricicola from Myricaria paniculate in China vs. C. fraxinigena from Fraxinus ornus in Italy vs. C. junipericola from Juniperus communis in Italy vs. C. pubescentis from Quercus pubescens in Italy vs. C. quercicola from Quercus sp. in Italy vs. C. rosae from Rosa canina in Italy) ( Senanayake et al. 2017 ; Shang et al. 2020 ).