Nyssaceae is a family of flowering trees sometimes included in the dogwood family (Cornaceae). Nyssaceae is composed of 37 known species in the following five genera: Among the extinct genera of the family are Mastixicarpum, very similar to Diplopanax, and Tsukada, an extinct relative of Davidia. In some treatments, Davidia is split into its own family, the Davidiaceae. Diplopanax and Mastixia are also sometimes separated into the family Mastixiaceae. The Angiosperm Phylogeny Group APG III system included the genera of Nyssaceae within Cornaceae. The APG IV system recognizes Nyssaceae as a distinct family