1. In the inbred line of Haplopappus gracilis KH-1 (2n=4), a new-shaped chromosome was found. The length of this chromosome was similar to chromosome 1 and this is J-shaped chromosome having centromere at the subterminal position.
2. From the distribution of the early condensing regions at mitotic prophase and the meiotic chromosome behaviour of the heterozygotes of J-shaped and V-shaped chromosome, it was suggested that the J-shaped chromosome was derived from the V-shaped chromosome by the appearance of a new centromere in the subterminal position and by the disappearance of the centromere in the median position.
3. The cause of the appearance of the new centromere in this chromosome was presumed to be an actuation of the suppressed centromere in the subterminal position and a suppression of the median centromere.