This investigation is more comprehensive in its taxo- nomic sampling of tribe Hydrangeeae than previous publications on floral morphology of the family. All genera of Hydrangeeae (sensu Hufford et al., 2001; Fig. 1) are included. The form and structure of postanthetic flowers of all genera of tribe Hydrangeeae and floral development. for all, except Platycrater and Broussaisia, are described in this investigation.