The American groundnut (Apios americana), also called potato bean, hopniss, hodoimo, and cinnamon vine, is a vine that grows edible beans and tubers. While it is native to the United States and southern Canada, it is only cultivated commercially in Japan, where it is known as hodoimo because of its similarity to the wild Apios fortunei plant that shares that name.
It is considered an undomesticated crop in most of its native range, though research at Iowa State University is investigating whether it could be domesticated for American agricultural use.