Pokeweed
You’ve probably never heard of this dreary-sounding plant, but pokeweed is actually pretty useful. Native Americans had used the roots, berries, and leaves of the plant as medicine for colds, coughs, and headaches, so the colonists started to do the same thing.
The important thing they had to remember, though, was that raw pokeweed can make you sick, or even kill you. You should always make sure that the plant is properly cooked, so it would usually be boiled for a long time. When you’re out in the wild and you’re running short on food, finding this would have been a godsend.