Young Moon Kim1P, Shukherdorj Baasanmunkh1, Nudkhuu Nyamgerel1, Dong Chan Son2, Gyu Young Chung3, Hyeok Jae Choi1

1Department of Biology and Microbiology, Changwon National University, Changwon, South Korea; 2Division of Forest Biodiversity and Herbarium, Korea National Arboretum, Pocheon 11186, South Korea; 3Department of Forest Science, Andong National University, Andong 36729, Korea

The section Subalbae belongs to subgenus Salix and is considered parallel to the European–West Asian section Salix, although some classifications include it within that section. Members of section Subalbae are characterized by lanceolate leaves with narrow apices and densely serrate margins. In this study, we examined extensive morphological characters and conducted comparative plastome-based phylogenetic analyses of three Korean species: Salix babylonica, S. pseudolasiogyne, and S. pierotii. Although these species share general morphological characteristics, several taxonomically informative differences were identified, including branch architecture, style development, and anther color. Principal component analysis (PCA) revealed partial overlap among species, but characters related to the sizes of leaves, bracts, ovaries, stamens, and styles contributed significantly to species differentiation, indicating that traditional taxonomic characters remain informative. Plastome phylogenetic analysis of 27 Salix species resolved two major clades corresponding to subgenera Chamaetia/Vetrix and Salix. The three focal species clustered with S. koreensis and S. matsudana within subgenus Salix, but formed two distinct groups. Despite previous treatments of S. pseudolasiogyne and S. matsudana as synonyms of S. babylonica, our results reveal clear distinctions among these taxa. Overall, the combined morphological and plastome-based phylogenetic evidence supports recognizing S. babylonica, S. pseudolasiogyne, and S. pierotii as distinct taxonomic entities within section Subalbae.

*This study was supported by the Korea National Arboretum (Grant No. KNA1-1-18-15-3) and “R&D Program for Forest Science Technology (Project No. RS-2021-KF001796)” supported by the Korea Forest Service (Korea Forestry Promotion Institute).