There are small appendages attached to the roots, which become distended with air, and thus carry the plant aloft to the surface, during the cool season.

Here it floats till the operation of flowering is over, when the vesicles burst, and by its own weight it returns to the bottom of the lake to ripen its seeds and deposit them in the soil; after which the air vessels again fill, and again it re-ascends to undergo the same process of fecundation.].