Trifoliate Orange (Poncirus trifoliata, syn. Citrus trifoliata) is a member of the family Rutaceae, closely relate to Citrus, and sometimes included in that genus, being sufficiently closely related to allow it to be used as a rootstock for Citrus. It differs from Citrus in having deciduous, compound leaves, and pubescent (downy) fruit. It is native to northern China and Korea, and is also known as the Chinese Bitter Orange.