Cytogenetic and Cytoecological Studies on some Japanese Species of Rubus IV

1) The flowering time of the polyploid of Rubus is later than that of the diploid, and the flowering time of the octoploid, which belongs to subgenus Malachobatus, is especially later than that of all the others. The octoploid, therefore, is physiologically isolated from all the other species.2) In the stem-cutting propagation, the diploid is earlier in the unfolding time of buds than the polyploid. Leaves of the diploid are more rapid in growth than those of the polyploid in the early stage of the cuttage. In the later stage, however, the polyploid is larger than the diploid in the growth of leaves.3) The leaves of the polyploid which grow from the buds of the stem-cuttings have a darker color than those of the diploid.4) The rooting of the stem-cuttings of the polyploid is mostly better than that of the diploid.