Carex chromosome numbers from Korean populations (eight taxa)

Abstract

<i>Carex</i> L. is the most species-rich genus in Korean flora (ca. 180 taxa) as well as worldwide (more than 2,000 species). One of the hypotheses explaining high species diversity in the genus is holocentric chromosomes, which miss constricted centromeres during cell divisions; chromosome fission and fusion events are possible. To provide fundamental biological information, we report the meiotic chromosomes of eight <i>Carex</i> taxa investigated from twelve populations, which include four Ulleung-do Island (oceanic island) populations. The taxa and chromosome numbers observed were <i>C. augustinawiczkii</i> (<i>n</i> = 27<sub>II</sub>), <i>C. bostrychostigma</i> (<i>n</i> = 22<sub>II</sub>), <i>C. egena</i> (<i>n</i> = 25<sub>II</sub>), <i>C. fusanensis</i> (<i>n</i> = 21<sub>II</sub>), <i>C. japonica</i> (<i>n</i> = 31<sub>II</sub>, 32<sub>II</sub>), <i>C. maackii</i> (<i>n</i> = 37 II ), <i>C. mollicula</i> (<i>n</i> = 32<sub>II</sub>), and <i>C. pediformis</i> var. <i>pedunculata</i> (<i>n</i> = 36<sub>II</sub>). Chromosome numbers of <i>C. augustinawiczkii</i>, <i>C. egena</i>, <i>C. fusanensis</i> (a Korean endemic), and <i>C. pediformis</i> var. <i>pedunculata</i> are revealed for the first time. <i>C. japonica</i> from Ulleung-do Island populations exhibits two chromosome numbers, which differ from the chromosome numbers reported from the Korean mainland (peninsula). More chromosome data are required to understand <i>Carex</i> species diversity in Korean flora.