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What’s the difference between nuts and seeds?

When it comes to nuts and seeds, it’s easy to get confused by name, size and other factors. Here’s our guide to work out which is which, along with some handy examples.

What is a nut?

The botanical definition of a nut in its simplest form is a seed contained in a hard shell which doesn’t naturally open to release the seed when it matures.

The culinary definition of a nut is much simpler and incorporates a whole range of edible plant parts. It’s often considered to be any edible kernel surrounded by a shell.

The hazelnut is a nut by nature as well as name (Photo: Ben Lee/WTML)
The hazelnut is a nut by nature as well as name (Photo: Ben Lee/WTML)

What is a seed?

A seed is a mature fertilised ovule of a plant which consists of three parts:

  • embryo – where the new plant forms if subject to the right conditions
  • endosperm - a food store
  • seed coat – a protective covering.

A seed may also go by the name of kernel, pip, pit or stone depending on its source.

To confuse matters, a nut can also be a seed. But a seed by definition is not a nut.

Seeds we commonly think of as nuts

Despite the name, peanuts are not really nuts - at least not in the botanical sense. The peanut grows underground, in a pod like peas and lentils. This means it is not classified as a nut but as a legume. This is reflected in the ‘pea’ part of the name.

The botanical definition means many foods we call nuts are actually seeds! Foods that fall into this trap include:

  • almonds
  • Brazil nuts
  • cashews
  • macadamias
  • pecans
  • pistachios
  • pine nuts
  • walnuts.

The term tree nut is often used to cover this group of seeds.

Technically, walnuts aren't really nuts (Photo: iStock.com/matricul)
Technically, walnuts aren't really nuts (Photo: iStock.com/matricul)

Nuts we commonly think of as seeds

One of the most common nuts to be mistaken for a seed is beech mast, produced by the beech tree. Prickly four lobed cases protect one or two triangular nuts which are an important food source for mice, voles, squirrels and birds.

The hornbeam tree also produces nuts which masquerade as seeds. Female catkins develop into papery, green winged fruits, known as samaras. At the base of each leafy bract is a small nut about 3-6 mm long.

Beech nuts grow in prickly cases (Photo: Ben Lee/WTML)
Beech nuts grow in prickly cases (Photo: Ben Lee/WTML)

Nuts and seeds of other UK trees

Thankfully, other tree nuts and seeds aren’t so tricky to identify! Here’s what to expect from some of our other most common trees.

  • Alder: seeds grow inside the tiny cone-like fruits. Alder often grows close to water and its seeds are designed so they can float along to a new home.
  • Ash: hanging together in bunches, the long, narrow seeds of ash are also known as keys.
  • Chestnut: the fruits of both horse chestnut and sweet chestnut are true nuts.
  • Hawthorn: a single seed is contained in each of the common hawthorn’s red haws. The haws of Midland hawthorn contain two.
  • Hazel: this time the name can be trusted - hazelnuts really are nuts.
  • Holly: seeds are encased in each small crimson berry.
  • Lime - seeds are held in little round pods in clusters of 4-10. They’re attached to a leaf bracket which helps them to float away on the wind.
  • Oak: the acorns of an oak tree are considered nuts.
  • Rowan: seeds can be found inside the clusters of small berries.
  • Silver birch: tiny winged seeds are lightweight to help them travel by wind or water before reproducing.
  • Sycamore: symmetrical V shaped wings have rounded ends. These are one of the most recognisable seeds, also known as ‘helicopters’.
  • White willow: often found growing near water, willows produce seeds that are fluffy, white and light enough to drift downriver.
Sycamore seeds are also known as helicopters (Photo: Steven Kind/WTML)
Sycamore seeds are also known as helicopters (Photo: Steven Kind/WTML)

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