2006 Volume 71 Issue 2 Pages 141-147
Chromosome numbers were determined for 61 individuals of Eleocharis kamtschatica, collected from 4 localities in Japan and 1 locality in Alaska. Seven continuous intraspecific aneuploids of 2n=41–47 were found, and those with 2n=41, 43, 45, and 47 are reported for the first time here. The most common number was, 2n=42, found in 36 (59%) of the individuals studied. The plants with 2n=42, 44, and 46 had 34 small chromosomes and 8–12 large chromosomes. The number of large chromosomes increased as the aneuploid number increased, and the size of the large chromosomes did not differ among aneuploids, suggesting that aneuploidy in E. kamtschatica might have arisen by chromosome duplication and not agmatoploidy. The 2n=45 plants had an intermediate karyotype of 2n=44 and 46, and might have originated from the hybridization of 2n=44 and 2n=46. However, the 2n=41=10L+31S, 2n=43=8L+35S and 2n=47=10L+37S most probably originated from nondisjunction during meiosis or an irregular meiosis configuration with multivalent chromosomes.
