2007 年 72 巻 3 号 p. 275-278
Four species of Japanese Scleria were used for karyomorphological studies. Chromosome numbers of S. mikawana (2n=20) and S. levis (2n=48) were determined for the first time. Our finding of 2n=30 for S. parvula and 2n=48 for S. terrestris differs from those of previous studies. Two major groups were identified in the genus Scleria by karyomorphological data: (1) low chromosome numbers and x=5, (2) high chromosome numbers (2n=48). These karyomorphological data support the taxonomical treatment of 2 sections by Ohwi (1944). The high chromosome numbers may arise by polyploidy of low chromosome numbers because chromosome sizes were almost equal in both. Therefore, chromosomal evolution in the genus Scleria may be caused by polyploidy, rather than aneuploidy.