Abstract: The distribution patterns of plants in the Northern Hemisphere are closely linked to their evolutionary history. The genus Lonicera, commonly referred to as honeysuckle, is widely distributed across the northern temperate zone, making it an ideal model for exploring the distribution patterns and driving factors of plants in the Northern Hemisphere. This study, based on 108 globally distributed Lonicera samples (57 species), covered 22 of the 25 subsections of Lonicera recognized by Rehder (1903) and Nakai (1938), analyzed 485 orthologous loci and plastid genomes to investigate phylogenetic relationships, and observed phylogenetic incongruence. QuIBL and f-branch analyses revealed that incomplete lineage sorting (ILS) is the primary driver of phylogenetic discordance, accompanied by widespread but weak introgression, with only a small proportion of triplets showing strong support for introgression with relatively high mixture weights. Biogeographic and diversity distribution analyses suggest that Lonicera originated in the Qinghai–Xizang Plateau (QXP) and/or East Asia, spread to North America and Europe, and established diversity centers in East Asia, Central Europe, and western North America. Our results support the hypothesis that the uplift of the QXP and global climate shift of the Eocene–Oligocene transition (EOT) were both evolutionary drivers, with varied ecological adaptability among various Lonicera lineages. This study provides new insights into the phylogeny and biogeographic evolution of Lonicera, while also serving as a reference for studies on the evolutionary history of plant and animal lineages.

Key words: biogeography, Caprifoliaceae, ecological analyses, phylogenomics, species diversification.