Spatterdock

[Swede]

Spatterdock is a perennial plant with leaves that arise from a large spongy rhizome. The leaves have a slit that makes them roughly heart-shaped, 8 to 16 inches long by 10 inches wide, and can float on the surface or stand above the surface on thick round (in cross section) stalks. Flowers are spiracle with 6 to 9 green sepals and yellow petals. Flowers can float on the water or stand above it. Fruits are oval with a flat top and greenish or yellowish in color. Spatterdock can spread from seeds or the rhizomes.

http://aquaplant.tamu.edu/database/emergent_plants/spatterdock.htm