This member of the Isoetaceae
family was given this name by Addison Brown in 1861. It is found
in the Southern Korea and probably in other parts of Asia, growing
on swamps and in lakes with little nutrition, down to two meters debt
and a pH around 7. The caudex can grow to three centimetre in
diameter, the leaves to 30 centimetres length.
japonica and I. coreana are quite close. Both are
submerged or amphibious. I. coreana produces megaspore
with irregular, branching crested ornaments on surface while I.
japonica produces megaspore that has evidently reticulate
ornaments. The trilobed caudex of Isoetes japonica consists
of two distinct structures, viz. Stem and Rhizophore, to which the
leaves and roots are respectively attached; but owing to the stunted
growth of the plant, all external morphological differentiation
between the two organs has been completely lost.
Also seen as member of the Juncaceae
and Lycopodiaceae families.