Isoetes, Linnaeus, 1753

Liu, Chenlai, Yu, Xiaolei, Song, Xiaoli, Shao, Jingjing, Chen, Yuchu & Liu, Xing, 2024, Two new diploid species of Isoetes (Isoetaceae: Lycopodiopsida) from Southeastern China based on morphological and molecular evidence, Phytotaxa 642 (1), pp. 37-49 : 44

Key to the species of the genus Isoetes in China

1. Corm 3-lobed .....................................................................................................................................................................................2

-. Corm 2-lobed .................................................................................................................................................................. I. longpingii

2. velum present......................................................................................................................................................................................3

-. velum absent.......................................................................................................................................................................................6

3. Megaspores 207–340 μm ...................................................................................................................................................................4

-. Megaspores 340–450 μm ...................................................................................................................................................................5

4. Megaspores 207–280 μm ......................................................................................................................................... I. shangrilaensis

-. Megaspores 280–340 μm............................................................................................................................................... I. taiwanensis

5. Megaspore ornamentation reticulate; microspore ornamentation tuberculate-echinate.................................................... I. orientalis

-. Megaspore ornamentation cristate-reticulate; microspore ornamentation levigate-granulate ..................................... I. yunguiensis

6. Leaves 2–9 cm long; growth in high elevation ............................................................................................................... I. hypsophila

-. Leaves longer than 9 cm; distuibuted in lowland sites.......................................................................................................................7

7. Megaspore ornamentation echinate or critstate or echinate-critstate .................................................................................................8

-. Megaspore ornamentation tuberculate or rugulate ............................................................................................................................9

8. Megaspore ornamentation echinate or critstate................................................................................................................................10

-. Megaspore ornamentation echinate-critstate................................................................................................................... I. baodongii

9. Megaspore ornamentation tuberculate ......................................................................................................................... I. changleensis

-. Megaspore ornamentation rugulate ............................................................................................................................... I. yuhangensis

10. Megaspore ornamentation echinate..................................................................................................................................... I. sinensis

-. Megaspore ornamentation critstate...................................................................................................................................... I. xiangfei