So... I'd recieved a small bag full of this plant from my girlfriend about three weeks ago.
It was sold to her as 'water wisteria' which it is most definitely not as you can see from the pictures. The LFS was up to their usual antics, charging a random amount for a plant that is incorrectly labeled.
Now, this plant naturally floats, i've managed to plant some of it with tweezers, both seem to be doing just fine as near as i can tell.
Now, as for actual structure, it appears that the leaves sprout directly from a very small rhizome like structure with the thread-like roots trailing behind.
That's odd... because this came as stems of plants with leaves in that shape and it literally exploded in her tank.
Not that i doubt you, but i have a few large stems of H. Difformis in my tanks and the leaves only bear a minor similarity to my eye... Is there a particular water condition or factor that would cause this?
It grows almost the same as h. difformis, hogs the surface if ignored so you want to trim it well to keep it down. No special attention required but the better the conditions, the nicer the leaf structure.