Dioscoreaceae (/ˌdaɪəˌskɔːriˈeɪsii/) is a family of monocotyledonous flowering plants, with about 715 known species in nine genera. The best-known member of the family is the yam (some species of Dioscorea). The APG system (1998) and APG II system (2003) both place it in the order Dioscoreales, in the clade monocots. However, the circumscription changed in the APG II system, with the 2003 system expanded to include the plants that in the 1998 system were treated in the families Taccaceae and Trichopodaceae.