A Potato Replacement: Arrowhead (Sagittaria latifolia)
Arrowhead is also sometimes called Indian potato or duck potato because the starchy tuber at the end of its rhizomes (a rhizome is essentially an underground stem) is edible and filling. Native Americans ate it often, and Lewis and Clark equated it to the potato and claimed it fit for trading. If it was good enough for them, it will be good enough for the survivor of the apocalypse to learn to identify and harvest.
The tubers can be baked in the edges of the fire desperately scrapped together by the cold and hungry Survivor, or they can be boiled if the Survivor has a vessel. The tubers can be dried and kept after roasting, making them a valuable long-term food source.
Arrowhead can be found in marsh-like settings, usually places with more permanent marsh conditions (rather than floodplains), although they are found in many parts of the Mississippi River basin.
To harvest them, the Survivor must dig around in the “muck” of the swamp bottom (with your hands or feet) and “hope to see the duck potatoes float to the surface,” according to survivalist Hank Shaw. Check out his blog for a recipe to use them (quickly, before your conventional kitchen is disintegrated in a nuclear explosion).
Identification: Grows in swampy ground or standing water. Leaves are 5-50 cm and are in the shape of an arrowhead. Small flowers with 3 white petals cluster the upper stem, usually 3 per bunch. More on this plant from the USDA.