Your turn
Each lab is one part of the video. Change things and see what happens.
Each lab isolates one idea from the video. The diagrams are simplified and not to scale.
Tap the buttons and see what happens.
Flip the bowl between the cook's view and the botanist's view. Which foods change sides?
Culinary categories follow taste and use; the botanical category follows plant anatomy. Compare the labels.
Tap a button. Which foods change?
Drag the slider. Watch the petals drop and the ovary swell into a tomato.
Scrub the time-lapse: pollination, fertilization, petal fall, then the ovary wall thickens around the seeds.
Slide it. What happens to the flower?
A schematic diagram: not to scale, no real timings.
Slice each food open. Which ones have seeds inside?
Section each food: seeds signal a ripened ovary. The carrot, a root, has none.
Tap to cut them open. Where are the seeds?
Pick a fruit and run the three-question berry test.
Apply the botanical definition: one flower, one ovary, a wholly fleshy wall, no stone.
Pick a fruit. Is it a berry?
Drag each food onto the part of the plant it came from. How many are fruits?
Sort each food by the organ it develops from. Fruits come from the flower's ovary (sometimes with a little help from nearby flower parts).
Drag each food to its spot on the plant.
Tap a fruit to send its seeds travelling: by animal, wind or water.
Three dispersal strategies: animals (fleshy fruit), wind (samaras), water (buoyant coconuts).
Tap a button to send a seed away.
Is a tomato a fruit or a vegetable? A cook says vegetable, because it goes in salads. A plant scientist says fruit! They are both right. They just ask different questions.
Every fruit starts as a flower. In the middle of the flower is a tiny room called the ovary. When pollen reaches the tiny eggs inside and joins with them, they start to grow into seeds. The petals fall off, and the ovary puffs up into a fruit.
Here is a trick: look for seeds! Tomatoes, peppers, cucumbers and pea pods all have seeds inside, so they are fruits. A carrot has no seeds. It is a root.
A banana is a berry! So are grapes and tomatoes. But a strawberry is not. Each little dot on a strawberry is a tiny fruit with one seed.
A plant cannot walk. Its fruit carries the seeds away. Birds eat fruit and drop the seeds far away. Some seeds fly on the wind, and a coconut can float on the sea.
Plants make their food from sunlight. Want to see how? Watch how photosynthesis works.
To a botanist, a fruit is the ripened ovary of a flowering plant, wrapped around its seeds.1 Every fruit starts life as a flower. After the flower is pollinated, tiny ovules inside the flower's ovary turn into seeds, and the ovary wall swells and thickens around them. That swollen ovary is the fruit.2 Taste has nothing to do with it, so tomatoes, cucumbers, peppers, pea pods and pumpkins are all fruits.4
flower → pollination → ovules become seeds + ovary swells = fruit
The fruit-or-vegetable argument goes round in circles because two groups use the same words for different jobs. A cook sorts food by taste and use: fruits are usually sweet or tart and end up in desserts and snacks, while vegetables are savoury and go into main meals.4 A botanist, a scientist who studies plants, ignores taste completely and asks only one thing: which part of the plant did this grow from?
| Food | Cook says | Botanist says | Why |
|---|---|---|---|
| Tomato | vegetable | fruit (a berry) | grows from the flower's ovary, full of seeds |
| Cucumber, pumpkin, zucchini | vegetable | fruit (a berry with a rind) | grows from the ovary, full of seeds |
| Bell pepper, eggplant | vegetable | fruit | grows from the ovary, holds seeds |
| Pea pod, green bean | vegetable | fruit | the pod is the ovary; the peas and beans are the seeds |
| Corn kernel | vegetable / grain | fruit | a small dry fruit, mostly seed |
| Carrot, beet | vegetable | root | no flower, no seeds |
| Potato | vegetable | tuber (underground stem) | no flower, no seeds |
| Broccoli | vegetable | flower buds | picked before the flowers open |
Neither side is wrong. "Is a tomato a fruit?" has two correct answers, depending on whether you mean the botanist's word or the cook's word.4
Look deep in the middle of a flower and you'll find a small swollen chamber at the bottom of the central stalk. That's the ovary, and it holds tiny ovules. Here's the sequence:
You can watch this happen on a tomato plant: the little yellow flowers fade, and a tiny green ball appears right where the middle of the flower was. That green ball keeps growing until it ripens into a tomato. The time-lapse in chapter 2 of the explainer above shows the same steps (it is a diagram, not to scale).
A few cultivated plants, such as seedless bananas, grapes, oranges and cucumbers, can grow fruit without fertilization. The fruit still grows from the ovary, so it still counts as a fruit; it just has no proper seeds. This is called parthenocarpy.1
Because a fruit is the part of the plant that holds the seeds, there's a handy rule of thumb: if it has seeds inside, it's probably a fruit; if it doesn't, it's probably a vegetable.6 Cut a tomato across the middle and you'll see seeds sitting in jelly inside several chambers. A pepper keeps a cluster of seeds near its stalk, a cucumber has rows of pale seeds down its middle, and a pea pod lines its seeds (the peas) up in a row. A carrot has none, because it's a root.
Not every fruit is full of seeds: some are seedless (above), and some, like cherries and peaches, hold just one seed inside a hard stone. That's why botanists use the flower-and-ovary definition rather than just counting seeds.
Botanists sort fruits into types, and the "berry" type causes the biggest surprises. In botany, a true berry grows from a single flower with a single ovary, and the whole ovary wall turns soft and fleshy, usually around several seeds, with no hard stone.56
| Fruit | True berry? | Why |
|---|---|---|
| Grape, blueberry, cranberry | Yes | one ovary, soft wall, several seeds5 |
| Tomato, banana, kiwi, eggplant | Yes | one ovary, soft wall5 |
| Pumpkin, cucumber, watermelon | Yes (a "pepo") | a berry with a tough, leathery rind5 |
| Orange, lemon | Yes (a "hesperidium") | a berry with a rind and juicy segments5 |
| Strawberry | No | the red flesh grows from the flower's swollen base; the dots are tiny separate fruits6 |
| Raspberry, blackberry | No | a cluster of little fruits from many ovaries in one flower5 |
| Cherry, peach, plum | No | one seed inside a hard stone (a "drupe")5 |
The strawberry is the strangest. Its juicy red part grows from the receptacle, the swollen tip of the stalk that holds the flower, not from the ovary. The little dots on the outside aren't simply seeds: each one is a tiny, hard, dry fruit (an achene) holding a single seed.6 Fun fact: the word "berry" originally meant "grape".5
Yes. An apple is an accessory fruit: most of the part you eat grows from the floral cup around the ovary, and the core with its seeds is the ovary itself.6 Pineapples, figs and mulberries are multiple fruits, made when many flowers fuse into one.5 And plenty of dry things are fruits too: acorns, walnuts, chestnuts and coconuts are fruits with a hard shell, grains like corn, wheat and rice are tiny dry fruits, and the whirling maple "helicopters" are fruits built for flying.24 (A Brazil nut, though, is a seed.4)
Here's the surprise: botany has no strict definition of "vegetable".4 It's a cooking word for savoury plant parts. Cooks call some botanical fruits vegetables too (tomatoes, peppers, cucumbers), but most vegetables come from other parts of a plant:
That's why a potato isn't a fruit: it's a tuber, a food store in an underground stem, with no seeds inside.4 Broccoli is interesting because it's picked as a bunch of unopened flower buds, before any of them could open and make fruit.
A plant can't walk, but its seeds need to reach new ground where they won't compete with their parent. Fruits are how flowering plants move their seeds, a job called seed dispersal.2
This is part of why flowering plants have been so successful: there are more than 300,000 species of them.2 If you want to know how the pollen gets to the flower in the first place, see how pollination works; for where a plant gets the energy to build a fruit, see how photosynthesis works.
The tomato argument once went all the way to the United States Supreme Court. In the 1880s, the US charged a tax on imported vegetables but not on fruit. Importers named Nix argued that tomatoes were fruits, so they shouldn't pay. On May 10, 1893, the Court decided in Nix v. Hedden that tomatoes counted as vegetables for the tax, because in "the common language of the people" they are served with the main meal, not as dessert.7
But the judges agreed with the botanists too. Their ruling says: "Botanically speaking, tomatoes are the fruit of a vine, just as are cucumbers, squashes, beans, and peas."7 The Court wasn't changing the science; it was deciding what an everyday word meant in a tax law.4
To a botanist, a fruit is the ripened ovary of a flowering plant, usually wrapped around seeds. It forms after a flower is pollinated: the ovules inside the ovary become seeds and the ovary wall swells into the fruit. Taste doesn't matter, so tomatoes, peppers and pea pods all count.
Both, depending on who's asking. Botanically it's a fruit (in fact a berry), because it grows from the flower's ovary and holds seeds. In the kitchen it's treated as a vegetable because it's savoury. In 1893 the US Supreme Court ruled tomatoes were vegetables for a tax on imports, while admitting that botanically they are fruits.
Yes. A cucumber grows from a flower and is full of seeds, so botanists call it a fruit. It's even a kind of berry with a tough rind, called a pepo, like pumpkins, zucchini and watermelons.
A potato is a tuber, a swollen underground stem that stores food. It doesn't grow from a flower's ovary and has no seeds inside, so it's a vegetable. (Potato plants do make small fruits above ground, but the potato we eat isn't one of them.)
Yes, an apple is a fruit, but a special kind called an accessory fruit. Most of the part you eat grows from the floral cup around the ovary rather than from the ovary itself; the core with the seeds is the ovary.
A true berry grows from a single ovary of one flower, with a fleshy wall and no hard stone around its seeds. Bananas, grapes, tomatoes and blueberries pass. A strawberry's red flesh grows from the swollen base of the flower, and each dot on the outside is a tiny separate fruit holding one seed, so it fails the test.
Many are. Acorns, walnuts, chestnuts and coconuts are fruits with a hard shell, and grains such as corn, wheat and rice are small dry fruits made mostly of seed. A Brazil nut, though, is a seed.