| 2. Leaves longer than 2 cm, all appearing to originate
at ground level (no obvious stem); multiple spores borne in an enclosed
space at the abruptly expanded base of individual leaves. Aquatic
species, growing submersed on lake bottoms. |
|
Isoetes |
| 2. Leaves shorter than 1 cm., spread out along obvious
stems; spores borne in sporangia, in the axils of some upper leaves
or in terminal strobili (cone-like structures). Terrestrial or wet
soil species, but not commonly submersed. The primary criteria listed
below can be difficult to grasp in the abstract, although the two
genera are easily distinguished with a little experience. |
|
3 |
|
