Four new Phragmidium (Phragmidiaceae, Pucciniomycetes) species from Rosaceae plants in Guizhou Province of China Author Sun, Jing-E Department of Plant Pathology, Agricultural College, Guizhou University, Guiyang, 550025, China Author Zhang, Qian Department of Plant Pathology, Agricultural College, Guizhou University, Guiyang, 550025, China Author Luo, Wen-Mei Department of Plant Pathology, Agricultural College, Guizhou University, Guiyang, 550025, China Author Yang, Yuan-Qiao Department of Plant Pathology, Agricultural College, Guizhou University, Guiyang, 550025, China Author An, Hua-Ming Department of Plant Pathology, Agricultural College, Guizhou University, Guiyang, 550025, China & Agricultural College, Guizhou University, Guiyang, 550025, China Author Wang, Yong Department of Plant Pathology, Agricultural College, Guizhou University, Guiyang, 550025, China yongwangbis@aliyun.com text MycoKeys 2022 2022-11-10 93 193 213 http://dx.doi.org/10.3897/mycokeys.93.90861 journal article http://dx.doi.org/10.3897/mycokeys.93.90861 1314-4049-93-193 DBF89CE4A6B7518BA94F6B181158D1D7 Phragmidium rosae-laevigatae J.E. Sun & Yong Wang bis sp. nov. Fig. 6 Diagnosis. Different from Ph. Jiangxiense mainly because of bigger urediniospores. Holotype. China. Guizhou Province: Panzhou city, 25°64'56"N, 104°84'35"W, 1800 m, 19 Jul 2021, on Rosa laevigata , coll. J.E. Sun, HGUP21036, ITS: OL684829, LSU: OL684840. Etymology. Referring to the host, Rosa laevigata , on which the fungus was first found. Description. Spermogonia and aecia not observed. Uredinia produced on the abaxial leaf surface, hypophyllous, subglobose to globose, powdery, 0.1-0.5 mm diam, yellow, peripherally parphyses, hyaline, 20-31 x 10-17 µm . Urediniospores square to diamond-shaped, oval to nearly spherical, 23-35 x 16-30 µm (mean 29 x 23 µm , n = 30), orange-colored, thick-walled 0.5-2.0 µm thick, colorless, regularly echinulate with stout spines on the surface. Telia scattered compact, hypophyllous, golden, 0.1-0.5 mm diam. Teliospores (immature) oval, 24-60 x 8-20 µm (mean 50.5 x 25.5 μm , n = 30), with apical papillae (4.0-7.0 μm high, n = 10), too immature to know how many cells, orange-yellow; pedicels swollen at the base, 15-26 μm long, colorless, disconnected easily; wall 0.5-2.0 μm thick. Rust diseases symptoms: As shown in Fig. 6 , Uredinia and telia, which are bright-yellow and powdery are produced almost simultaneously on the lower surface of the yellowing and wilting leaves. Figure 6. Phragmidium rosae-laevigatae sp. nov. (HGUP21036, holotype) on Rosa laevigata a gross features of infected leaves b uredinia and telia on a leaf c longitudinal section of telium d immature teliospores e longitudinal section of uredinium f-h urediniospores. Scale bars: 1 mm ( b ); 50 µm ( c, e ); 12.5 µm ( d, f - h ). Habitat. Rosa laevigata . Known distribution. China, Guizhou Province. Additional material examined. China . Guizhou Province : Panzhou city, 25°61'81"N, 104°83'61"W, 1790 m , 19 Jul 2021 , on Rosa laevigata , coll. J.E. Sun , HGUP21037 . Notes. Phylogenetically, Phragmidium rosae-laevigatae kept a close relationship to Ph. leucoaecium , Ph. japonicum and Ph. jiangxiense (Fig. 1 ). Morphologically, Phragmidium rosae-laevigatae has bigger urediniospores than Ph. jiangxiense (23-35 x 16-30 µm vs. 15-23 x 11-18 μm ), but the uredinia and urediniospores of Ph. leucoaecium and Ph. japonicum were not observed ( Liu et al. 2020 ). The comparison of DNA base composition also supported morphological conclusion. Thus, this fungus was also introduced as one novel taxon herein.