Hydrangea Gronov. genus doubtful

Hortensia Comm. genus synonym

Adamia Wall. genus synonym

Cyanitis Reinw., 1823 genus accepted

Sarcostyles C.Presl ex DC. genus synonym

Cornidia Ruiz & Pav. genus synonym

Platycrater Siebold & Zucc. genus synonym

Hortensia Comm. ex Juss., 1789 genus synonym

Edwinia A.Heller genus synonym

Neodeutzia Small genus synonym

Kirengeshoma Yatabe genus accepted

Deinanthe Maxim. genus synonym

Calyptranthe (Maxim.) Nakai genus synonym

Hydrangia L. genus synonym

Cianitis Reinw. genus synonym

Broussaisia Gaudich. genus synonym

Deutzia Thunb. genus accepted

Decumaria L. genus synonym

Fendlera Engelm. & A.Gray genus accepted

Fendlerella A.Heller genus accepted

Hydrangea Gronov. ex L. genus accepted

Philadelphus L. genus accepted

Carpenteria Torr. genus accepted

Jamesia Torr. & A.Gray genus accepted

Whipplea Torr. genus accepted

Forsythia Walter genus synonym

Dichroa Lour. genus synonym

Calyptranthe (Maxim.) H.Ohba & S.Akiyama, 2016 genus doubtful

×Didrangea J.M.H.Shaw genus synonym

Heteromalla (Rehder) H.Ohba & S.Akiyama genus synonym

Macnemaraea Willemet genus synonym

Syringa Tourn. ex Adans. genus synonym

Schizophragma Siebold & Zucc. genus synonym

Pileostegia Hook.f. & Thomson genus synonym

Cardiandra Siebold & Zucc. genus synonym