Chromosome numbers of the Chinese Isoetes and their taxonomical significance
中国水韭属植物的染色体数目及其分类学意义

Chromosome numbers of four species of Isoetes from China are reported. The basic chromosome number in the four species is x=11. A chromosome number of 2n=22 was reported for the first time in I. hypsophila Hand.-Mazz. The 2n=22 was also found for I. taiwanensis DeVol, being consistent with previous report. I. sinensis Palmer from China has a chromosome number of 2n=44, which is different from that reported for I. sinensis Palmer from Japan (2n=44, 65, 66, 68). Another species of Isoetes from the Yunnan-Guizhou Plateau, which had previously been identified as I. japonica A. Br., has been shown to have a chromosome number of 2n=22, which is completely different from that reported for the latter species (2n=66, 67, 77, 87, 88, 89). More intensive studies on this new species should be made. Data from cytology and morphology of Isoetes species in China suggest that they may provide valuable clues for a better understanding of the origin and evolution of the genus Isoetes in East Asia.