<i>Carex</i> (Cyperaceae) chromosome numbers (six species) from Korean populations

<i>Carex</i> L. is one of the most species-rich genera of flowering plants, comprising more than 2,000 species worldwide and approximately 180 taxa in Korea. In addition to its high species diversity, the genus exhibits considerable variation in chromosome number among species and even among individuals within a species. This exceptional variation has been suggested to be associated with the holocentric chromosome structure of <i>Carex</i>. Among the approximately 180 <i>Carex</i> taxa in the Korean flora, chromosome numbers have been reported for 39 taxa in 20 sections, ranging from 2<i>n</i> = 12 to 2<i>n</i> = 108. In the present study, chromosome numbers were investigated. Meiotic chromosomes were observed in four species, and somatic chromosomes were examined in two species: <i>Carex miyabei</i> Franch. (<i>n</i> = 43_II), <i>C. brevispicula</i> G. H. Nam & H. Y. Chung (<i>n</i> = 34_II), <i>C. tristachya</i> Thunb. (<i>n</i> = 21_II), <i>C. laevissima</i> Nakai (<i>n</i> = 54_II), <i>C. siderosticta</i> Hance (2<i>n</i> = 12), and <i>C. splendentissima</i> U. Kang & M. Chung (2<i>n</i> = 12). The chromosome number of <i>C. laevissima</i> is reported here for the first time. Meiotic chromosomes were approximately 1 μm in length and were observed as bivalents, whereas somatic chromosomes ranged from 1.2 to 4.8 μm in length. None of the chromosomes exhibited distinct, localized centromeres or conspicuous primary constrictions. The accumulated cytological data should be evaluated in a phylogenetic context together with other morphological characters.