Contributed by Guy L. Nesom and Alan S. Weakley
A genus of about 40 species, shrubs and trees, of the Old World. Ligustrum is a monophyletic group phylogenetically embedded within Syringa (Li, Alexander, & Zhang 2002; Li et al. 2012; Dong et al. 2022). Li et al. (2012) recommended treating Ligustrum as series Ligustrae of Syringa, but species combinations have not been made. An alternative approach of segregating Syringa into monophyletic genera is also plausible.