Peanuts Aren't Nuts—They're Legumes Growing Underground

The next time someone offers you a bowl of peanuts, you can casually drop this botanical bombshell: they're munching on legumes, not nuts. Despite what the name suggests, peanuts have more in common with chickpeas and lentils than with almonds or walnuts.

Peanuts (Arachis hypogaea) belong to the Fabaceae family, the same plant family that includes over 19,000 species of beans, peas, and soybeans. True nuts—like acorns, chestnuts, and hazelnuts—develop from a single ovary and remain closed when they mature. Peanuts, on the other hand, grow in pods that split open naturally when ripe, just like their legume cousins.

The Underground Secret

What really sets peanuts apart is their bizarre growing process called geocarpy. After the peanut plant's yellow flowers self-pollinate above ground, they do something remarkable: they send shoots called "pegs" down into the soil. The peanuts then develop underground, hidden in their distinctive ridged shells.

This subterranean lifestyle is extremely rare in the plant kingdom and completely unlike tree nuts, which mature on branches in plain sight. It's also why peanuts are sometimes called "groundnuts" or "goobers" (from the Kongo word nguba).

So Why Do We Call Them Nuts?

The confusion is understandable. In kitchens and grocery stores, peanuts are grouped with cashews, almonds, and pecans. They have a similar crunchy texture, rich flavor, and high oil content. Culinarily speaking, they behave like nuts—perfect for snacking, baking, and making butter.

But botanists classify plants by their reproductive structures, not their taste or culinary applications. By that scientific standard, peanuts are definitively legumes, even if your trail mix doesn't care about the distinction.

The Triple Identity

Peanuts actually juggle three classifications depending on who's categorizing them:

• Botanically: Legumes (family Fabaceae)
• Agriculturally: Oilseeds (grown for their high oil content)
• Culinarily: Nuts (used like tree nuts in cooking)

This triple identity makes peanuts one of the most misunderstood foods in your pantry. They're also nutritional powerhouses—packed with protein, healthy fats, and fiber—traits they share with both their legume relatives and their nut impostor friends.

Next time you're at a ballgame cracking peanut shells, remember: you're enjoying a underground-growing legume that's been masquerading as a nut for centuries. And honestly? It's pulled off the disguise pretty well.