Difficulties in evaluating the meiosis inRosahybrids were found to be due to stickiness caused by hybridization in this genus. In sticky meiosis, the form and behaviour of chromosomes are changed and dense chromatin mass of different multivalent-like configurations are formed; but in spite of this, the two divisions are often completed. The stickiness varies very much in degree, and complete stickiness to almost normal meiosis can be observed in the same plant. Though stickiness was found to be caused by physiological conditions too in other material, the observation that it was found in hybrids mostly in our studies, indicates that this phenomen in roses is a result of an interaction between the genotype and the environment.