Potato bean (Apios americana) — also called hopniss, groundnut, Indian potato or American groundnut — is the starchy, protein-rich tuber of a slender native North American climbing legume. Unlike most edible tubers it grows not as a single swollen root but as a beaded string of small, knobby, brown-skinned tubers strung like rosary beads along an underground runner. Under the thin skin the flesh is dense, ivory to faintly yellow, and firmer than a potato; cooked it is mealy and satisfying with a warm, nutty, faintly beany taste — closer to a chestnut or a floury bean than to a true potato. Because it is a legume it carries far more protein than a potato, and it fed Indigenous peoples and early colonists across the eastern woodlands long before the potato reached North America.