The American groundnut is a member of the legume family. Its potato-y tubers (technically rhizomes) are extremely high in protein, and were dried or boiled as a staple in the diets of many Native tribes (plus that of the settlers). The flowers are gorgeous and showy, but the vines can grow to 10 feet and will take over a garden. It was never exactly domesticated in the US, but it escaped to Japan about 100 years ago and they have a good time cultivating it.