Euonymus, a cosmopolitan genus of the family Celastraceae, has its species diversity centered in East Asia. It exhibits a complex pattern of morphological variation, making its taxonomy difficult. Monophyly of the genus remains uncertain, and the evolutionary implications of the infrageneric division and delimitation of many species are debatable. In this study, we sampled a total of 62 accessions representing 48 species/taxa covering a broad range of diversity of the genus and its allies. We first investigated the phylogeny of