Getting Food From Water by Gene Logsdon.
So I was thumbing through this book on Aquaculture, and came across cattails. Root rhizomes, young shoots, young stalks, and pollen are all edible. Fresh vegetable fall through winter.
The rhizomes are harvested, cut to 6" and dried. They are then ground into flour. Cattails will produce 30 tons of flour per acre dry weight. This is more than 10 times wheat production. This flour contain more protein than corn or rice and more fat and minerals than corn, rice or wheat.
Pollen is also collected to be used as flour. Takes about 30 male flowers to produce enough for pancakes.
Makes me want to grow cattails in my duck pond out flow stream. Probably help filter the water also.