[en] In order to investigate the joining process a plant, Haplopappus Gracilis, which has only four chromosomes in the diploid form, was cultured and root tip cells were collected and staining techniques were developed. Two staining techniques, Giemsa and Feulgen, both give clearly stained chromosomes showing characteristic banding such that each chromosome can be identified individually. The banding is especially convenient for the identification of the telomeres of the different chromosomes. Root tip cells were exposed to X radiation and then collected at the following metaphase using a colchicine treatment, the cell were stained and the preparation were examined for chromosome aberrations which showed joining such as dicentrics or translocations. When such a type of aberration was found, the banding pattern was used to identify the chromosomes involved and the position of joining. Results of this investigation will be presented which show that in this plant cell the joining of a broken end to a normal telomere is occurring, in accordance with the prediction of the molecular theory