Karyological studies on two species of Compositae from the Hengduan Mountains, SW China Intergeneric hybrid of Dendranthema×grandiflorum “Aoyunhuoju” and Ajania pacifica and its taxonomic implications A Revision of Ajania potaninii ( Krasch.) Poljak. Group (Compositae) Intergeneric cross-compatibility between Dendran-thema ×grandiflorum and Ajania pacifica and the seed sets of their F1 progenies in different conditions of backcross, selfing and open pollination