Carex chromosome numbers from Korean populations (eight taxa)

Abstract

Carex 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 Carex taxa investigated from twelve populations, which include four Ulleung-do Island (oceanic island) populations. The taxa and chromosome numbers observed were C. augustinawiczkii (n = 27_II), C. bostrychostigma (n = 22_II), C. egena (n = 25_II), C. fusanensis (n = 21_II), C. japonica (n = 31_II, 32_II), C. maackii (n = 37 II ), C. mollicula (n = 32_II), and C. pediformis var. pedunculata (n = 36_II). Chromosome numbers of C. augustinawiczkii, C. egena, C. fusanensis (a Korean endemic), and C. pediformis var. pedunculata are revealed for the first time. C. japonica 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 Carex species diversity in Korean flora.