Among several tentative species and hybrids belonging to the genus Schoenoplectus (Cyperaceae), Hatabe-kangarei and closely related species, S.triangulatus and S.mucronatus, were analyzed 21 morphological characters by means of principal component analysis. As a result, Hatabe-kangarei was identified to be a new species because their three plants formed different clusters each another. Moreover, the inter- and intraindividual variations of chromosome number were found in root-tip cells and Hatabe-kangarei was considered to be polyploid of the other two species.
The inter- and intraindividual vriations of chromosome number were found in root-tip cells of eight kinds of plants in addition to above three species : S.juncoides ssp.hotarui ; 2n=35〜44, S.juncoides ssp.juncoides ; 2n=66〜74, S.triqueter, 2n=37〜42, S.lacustris ssp.creber, 2n=36〜44, S.chuanus ; 2n=64〜70, S.mucronatus f.tataranus ; 2n=37〜44, S.juncoides ssp.hotarui x S.sp.(=Inusankaku-hotarui) ; 2n=56〜60, S.juncoides x S.chuanus (=Nehiki-sankakuhotarui) ; 2n=48〜58. The variation, thus, must be widespread in this genus. In culm-apex cells, while, the variation was none or smaller than that in root-tip cells. This fact suggest that the mechanism of chromosomal variation was different betweeen root-tip cells and culm-apex cells.