Sagittaria latifolia otherwise known as Arrowhead or Duck Potato
Today I took my Ontario Wildflowers book down to the lake to see what I could identify. I was curious to find Wapato as I've come across it a number of times while reading into edible plants. These whorls of large white flowers and even larger arrowhead leaves produce edible tubers deep underwater, growing in hard water areas and are food for beavers, porcupines, muskrats and ducks. Native people also historically relied on these "wild potatoes" as a starchy, filling food source and actually frequently cultivated the plants in shallow waters with no current. The ripe tubers are white with purple skins and can be found floating freely in late August and early September (don't disturb the ecosystem by digging for them) They can be eaten raw or cooked 15 - 20 minutes in much the same way you'd cook potatoes: roast, fry, boil etc. and have much the same consistency but with a chestnut flavour. The late summer buds and fruits of the Wapato flower are also edible and make an aesthetically pleasing contrast to deep green salad leaves.