Dioscoreaceae /daɪɒˌskɔəriˈeɪsiː/ is a family of monocotyledonous flowering plants, with about 750 species in eight or nine genera. The best-known member of the family is the Yam (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.