Flower power

Follow these instructions to take a peek inside a flower and learn the names of all its parts.

Safety

A knife or a blade presents a cutting danger. Please use with appropriate supervision.

You will need

  • flower
  • knife or a blade – get an adult to help you
  • magnifying glass (optional)
  • pencil and paper.

What to do

  1. Go outside and find yourself a flowering plant (avoid daisies, roses and irises as it is hard to see their reproductive parts). Pick just a few flowers (don't be greedy) and take these back to a well lit bench.
  2. Look at your flower carefully and then draw it. Try labelling the petals and the sepals (have a look at our diagram below first).
  3. Very carefully, cut down the middle of the flower, so the flower is in two halves. Try to get a nice, even clean cut. Draw what you can see inside the flower.
  4. Have a look at our diagram and see if you can label the sepals, stamen, stigma, style and ovary of your flower.
  5. Look inside the ovary – can you see the ovules. These develop into seeds when they are fertilised.

flower cross section drawing with petal, stamen, sepal, ovary, ovule, style and stigma labelled

Overview of flower parts

  • Stamen: Male part of the flower that produces pollen. The stamen is made up of the anther at the top, which makes the pollen, held up by the filament.
  • Carpel: Female parts of the flower. Made up of the sticky stigma (an exposed part where the pollen first touches), the style (the tube the pollen travels down), the ovary and the ovules (which develop into seeds after pollination).
  • Petals: Bright coloured, often using colours invisible to the human eye such as ultraviolet, and perfumed attractants to insects.
  • Sepals: This circle of modified leaves encloses and protects the flower before it opens.

Note: All flowers are different and they will not all look like the classic flower in the diagram – especially some of our native flowers.

What's happening

The first flowering plants (angiosperms) appeared in the world at least 132 million years ago, maybe more, and are the largest and most diverse plant group, making up 80 percent of all green plants.

Red hibiscus flower © Nick Pitsas

The flower is the reproductive part of an angiosperm. Some flowers can self-pollinate, but most cross-pollinate (pollinate with another plant or flower). Once the pollen sticks to the stigma, it starts an impressive descent. It first germinates and then extends a tube to grow down through the style into the ovary. Once there, it discharges two sperm cells into the embryonic sac (this is inside the ovule). Both sperm cells fertilise cells in the embryonic sac, in a process known as double fertilisation. Once fertilised, the ovule develops into a seed.

The fruit then comes along – a fruit is a mature ovary. Fruits protect the seeds and aid in their dispersal. Fruits like apples and pea pods are examples of a simple fruit as they have developed from a single ovary. A luscious raspberry however, is an aggregate fruit, as it comes from several ovaries that were part of the same flower. For wild and wacky reproductive antics try the pineapple, as they develop from separate flowers entirely.

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