Abstract: The genus Macrocarpium has been accepted only by a few scholars since its separation from Cornus L. by T. Nakai in 1909. Bentham,  Hooker,  Hutchinson and the others consider that the ovary of Macrocarpium is 2-celled and the genus should be placed back into Cornus. We have discovered that are generally I-celled.  In addition, Macrocarpium is different from Cornus in basic chromosome number  (X),  flowering physiological character,  inflorescence type and involucral scale. Thus the genus Ma-crocarpium (Spach) Nakai should be reaffirmed.