Chemotaxonomic Insights into Korean Daphne spp. and Wikstroemia spp. by Integrating Flavonoid Contents with Ecological Factors

The placement of <i>Daphne genkwa</i> has long been controversial, as its intermediate morphological traits blur the boundary between <i>Daphne</i> and <i>Wikstroemia</i>. To address this challenge, we adopted a chemotaxonomic approach, integrating flavonoid contents with ecological indicators, as an independent line of evidence complementing morphology and molecular data. Using UPLC-UV, six flavonoids were quantified from 16 Korean populations representing six taxa. Multivariate analyses clearly distinguished <i>Daphne</i> and <i>Wikstroemia</i>, with <i>D. genkwa</i> and <i>W. ganpi</i> forming closely related but separate clades. Ecological factors such as precipitation and canopy openness significantly affected flavonoid levels, particularly luteolin 7-<i>O</i>-glucoside and yuankanin. However, the diagnostic flavonoid fingerprints remained consistent across habitats. This study demonstrates that integrating chemical and environmental perspectives can strengthen taxonomic frameworks and support both classification and chemotaxonomic evidence in Thymelaeaceae, offering a methodological basis for future comparative studies across related plant families.