When you are in a marshy area, you will probably find cattails. This grass has many uses when you are in the wild, from food to hygene.
In the late fall, just when you DON'T want to dig around in cold water, is the best time to harvest the startchy cattail roots. They have been putting energy into the roots all fall to survive the winter and are good to put into stews. Cut off the outer skin as that can be tough to chew through.
If you have a small wound, the fluff from an older cattail will be a good substitute for gause. It can also be used, along with finely shredded birch bark, as a menstral pad. The cattail soaks it up and the birch bark has slightly anticeptic properties.