A bit nutty

These edible seeds are packed with fiber, protein, and healthy fats.

Hazelnuts

Frilly husk covers all but the tip of the nut.

The shells of these large nuts are the hardest among all nuts.

The shell changes color from green to beige as the seed ripens, opening with a pop.

The two halves of the wrinkly fruit are separated by a partition.

A true nut is a hardened fruit containing one seed. False nuts develop inside fruits, and are more like the core of an apple.

This shell is a fruit’s fleshy body that happens to be hard. This is a seed and not the entire fruit.

Hollow seeds are creamy white with a clear liquid inside.

True nuts, such as chestnuts, acorns, and hazelnuts, are hard fruits containing a seed. Many of the nuts we eat are actually the seeds of fruits, or false nuts. To avoid confusion between the two, all edible nuts are called culinary nuts.

Acorn (true nut) Brazil nuts (false nut)

Nuts have been eaten by humans for thousands of years. Their high fat and protein contents make them a nutritious food. They do not rot or perish quickly, so early humans could store them for the winter months. Many culinary nuts are the seeds of fleshy stone fruits similar to plums,

Cashew stalks swell as the fruit ripens.

The edible seed is covered by a thin, reddish brown seed coat.

Hollow where nuts were cracked and ground with a stone by ancient people about 10,000 years ago. Cashew nuts

A toxic resin in the cashew shell can irritate the skin.

These wrinkled nuts have a buttery flavor.

Extra-hard shell can be cracked open by birds with very tough beaks.

A spiny sheath protects up to three developing nuts. Stubby pine nuts can be up to 3 in (8 cm) long.

including almonds, pistachios, coconuts, English walnuts, pecans, and cashews, while pine nuts are seeds found inside pine cones. Peanuts are the strangest so-called nut. Once pollinated, peanut flowers push a stalk into the soil to produce an underground bean pod containing up to four nutlike seeds. Since they grow beneath the soil, they are also known as groundnuts. Of the nuts shown here, hazelnuts and sweet chestnuts are the only “true” nuts. Their hard shells are the flesh of the fruit, while the part we eat is the seed.