American groundnuts

The seeds — and better-known tubers — of Apios americana, a climbing legume native to North America. Indigenous peoples cultivated it long before European contact as a dual-purpose crop: the small underground tubers are rich in protein for a root vegetable, while the seeds cook much like beans. The tubers can be dried and ground into a flour for baking, or used as a natural thickener and sweetener base. As a perennial that fixes its own nitrogen, American groundnut attracts interest from breeders and sustainable-agriculture researchers looking for low-input, soil-building food crops suited to temperate climates.