Flat leaves:
Plants in relatively deep water (more than 3-4 cm) adopted a floating habit, with flat leaf margins.
These floating leaves were also much larger than the leaves of the
terrestrial individuals. I measured the longest leaf on this plant as being about 11 cm (4.25 in) from base to tip.
A few more examples of flat leaved plants include these in nearly still water
and these in the currents.
It was easy to find plants with both flat leaves and recurved margins, so I'm sure this is just a response to the conditions and is
not anything genetically fixed.
