There are three subfamilies : Rubioideae , Cinchonoideae and Ixoroideae . While the limits of the Rubioideae remained almost unchanged in the face of molecular studies , the Antirheoideae was showen to be polyphyletic , while the Ixoroideae was broadened and the Cinchonoideae narrowed . The genera are distributed into tribes , and these placed in one of three recognized subfamilies .