Abstract:A cytological study of Drymotaenium miyoshianum Makino was carried out. The somatic chromosome number in root-tip cells of D. miyoshianum is found to be 2n=72. The karyotype formula is 2n=2x=72=18m+26sm+24st+4T. The karyotype belongs to 3B type. The chromosomes range in length from 1.74 to 4.61μm, with the ratio of the longest to the shortest 2.65. The index of karyotype asymmetry (As.K%) is 71.24. The karyotype of D. miyoshianum Makino was reported for the first time. The reproductive type in D. miyoshianum Makino is sexual diploid. Based on our study and previous data, the significance of chromosome number in phylogeny was discussed.