Perforated ray cells are identified for the first time in the Korean species of Deutzia glabrata, Deutzia sieboldiana, Hydrangea paniculata, and Philadelphus schrenckii that belong to Hydrangeaceae but not observed in Deutzia gracilis. These ray cells have simple to scalarifrom perfora-tions in Deutzia glabrata which have vessel elements with scalariform perforations, and have scalariform to reticulate perforations in Deutzia sieboldiana, Hydrangea paniculata, and Philadelphus schrenckii which have vessel elements with scalariform perforations. Thus, the perforations of ray cells in Korean Hydrangeaceae appeared not to be exactly the same as the types of scalariform perforation plates in the vessel elements of same wood .