Peanuts Are Nuts

Peanuts are legumes, in the same plant family as peas, beans, and lentils. True nuts, like almonds, walnuts, and hazelnuts, grow on trees and are technically a hard-shelled fruit. Peanuts grow underground on a small annual plant; the flower stalk bends down and pushes the developing pods into the soil to ripen, which is why they are sometimes called groundnuts. Botanically they have far more in common with the chickpea than the cashew. The reason they get lumped with nuts is purely culinary and practical: they are roasted, salted, and eaten like nuts, and crucially they can trigger severe allergies similar to tree-nut allergies, so allergy advice sensibly groups them together. But on the plant family tree, the peanut is a bean wearing a nut costume. The only thing nutty about it is the name and the marketing.