Four rings, one job

What Is a Flower Made Of?

A flower is built in rings, and the ring in the middle is the one that turns into a fruit.

Every fruit you have eaten was once the centre of a flower.

Step 1 of 5

The petals are the outermost ring but one.

Outside them sit small green flaps called sepals, which wrapped the bud before it opened. Petals are the next ring in.
Step 2 of 5

Inside the petals is a ring of stalks making pollen.

Each stamen is a thin stalk with a dusty head. That dust is pollen, and each grain carries half of what is needed to make a seed.
Step 3 of 5

And right in the middle is the part that becomes the fruit.

The carpel has a sticky top to catch pollen, a stalk, and a swollen base called the ovary. Inside the ovary are the eggs that become seeds.
Step 4 of 5

When pollen arrives, the ovary starts to swell.

The petals have done their job and drop off. The ovary thickens around the developing seeds, and what grows is a fruit.
Step 5 of 5

So the shape of a fruit tells you about the flower.

An apple core is the old ovary and the pips are the eggs. A strawberry's specks are separate tiny fruits, each from its own carpel in one flower.

A cucumber, a tomato and a pea pod are all ovaries with seeds in them, which makes every one of them a fruit.

The short version

A flower is rings of parts around a central ovary — and once pollen arrives, that ovary swells into the fruit and its eggs become the seeds.

Cut an apple across the middle. The star of pips is the plan of the flower's carpel, still visible months later.