2007 Volume 57 Issue 3 Pages 219-232
Cytological observations of the Japanese Gymnocarpium oyamense revealed the presence of diploids, triploids and tetraploids (x=40). Diploids have smaller spores than tetraploids. The Japanese diploids and plants suspected of being diploids because of their small spores (<34 μm) occur in the Kanto district and disjunctly in Mie Prefecture. Tetraploids and presumed tetraploids with large spores (>35 μm) are widely distributed from western Kanto westward to Shikoku, and are allopatric with the diploids. In China, suspected diploids are widely distributed in the inland provinces of Henan, Sichuan, Yunnan, Shaanxi and Gansu; tetraploids are mainly in the eastern provinces of Anhui, Jiangxi, Hunan, Guizhou, and Sichuan. The Japanese plants are distinct from the Chinese plants in the number of annular cells, regardless of ploidy level, but do not differ in spore ornamentation. Plants of Taiwan, Luzon and Seram differ from the Japanese and Chinese plants in the large muri on the perispore, and also from the Japanese plants in the number of annular cells. These variations suggest polyploidization after differentiation of the Japanese and Chinese populations, and a distinction between the temperate and tropical populations.
