ヤクシマノギクの染色体数および核型  [in Japanese] On chromosome number and karyotype of Aster ageratoides subsp. Yakushimensis  [in Japanese]

The chromosome number, 2n=72, was counted in Aster ageratoides TURCZ. subsp. yakushimensis KITAM. and the karyotype was analized. As the basic chromosome number being 9 in the genus Aster (HUZIWARA, 1957), this subspecies is considered to be an octaploid. Eight chromosomes of them which are considered to be four pairs have a secondary constriction. These four pairs of chromosomes are different from one another in the length and the form. Considering the lack of uniformity of these four pairs, this subspecies may be an allopolyploid. Since there is no short chromosome, the karyotype of this subspecies is considered to be L-chromosome type (IRIFUNE et al. 1985). This subspecies has affinity with A. ageratoides subsp. ovatus in flower color, leaf shape and hair type, but the karyotype of the latter is L・S-chromosome type. The difference of the karyotype between both subspecies suggests that subsp. yakushimensis has not originated directly from subsp. ovatus by the polyploidization of chromosomes.