Carex (Cyperaceae) chromosome report from islands in west and southwest of the Korean Peninsula: Additional aneuploid and polyploid populations

Carex L. is the most species-rich genus in the world, with more than 2,000 taxa, as well as in Korea, with about 180 taxa. The great diversity has been linked to holocentric chromosomes in the genus. To understand cytogenetic diversity in island Carex populations, we conducted chromosome studies on islands west and southwest of the Korean Peninsula, where 93% of the islands of Korea are located. From seven islands in the area, we observed two species in Carex sect. Mitratae and two species in sect. Siderostictae: Carex breviculmis (n = 34 II), C. tristachya (n = 21 II), C. ciliatomarginata (2n = 12), and C. siderosticta (2n = 12, 18). All of the taxa studied had chromosome numbers identical to those on the mainland. However, C. breviculmis showed a different number from a previous report on Saengildo Island in southern Korea (n = 32 II), and triploid populations of C. siderosticta from islands were identified for the first time. Further cytogenetic research is needed to gain a better understanding of Carex diversity on the mainland and islands of Korea.