Plant Reproduction

Lessons

Primary 6 · Science and Elementary Technology

Plant Reproduction

5 lessons

Lesson 1 of 5

Parts of a Complete Flower

25 min

Let's begin

At break time, Keza picks a red hibiscus flower from the school hedge. She gently pulls off the big petals one by one. Hidden in the middle she finds a long, thin stalk with a sticky, fluffy tip, and around it lots of tiny tips covered in yellow dust. The dust sticks to her fingers.

"Why does a flower need all these parts?" she asks. The answer is that a flower is the part of the plant that makes seeds. Each part has a job in making new plants.

A complete flower

Flowers are the reproductive organs of flowering plants. A complete flower has all four kinds of parts: sepals, petals, stamens (male) and a pistil (female). Hibiscus, bean and passion-fruit flowers are complete flowers.

The outer parts

Flower stalk (pedicel): holds the flower up and attaches it to the branch.
Receptacle: the top of the stalk, where all the other parts are attached.
Sepals: small, green, leaf-like parts that protect the flower while it is a bud. All the sepals together are called the calyx.
Petals: usually big and brightly coloured, often scented, to attract insects and birds. All the petals together are called the corolla. Grasses and maize have tiny petals or none, because the wind, not animals, carries their pollen.

The male part: the stamen

The stamen has two parts:

the anther, which makes pollen. Pollen grains carry the male sex cells.
the filament, a thin stalk that holds the anther up.

The female part: the pistil (carpel)

The pistil, also called the carpel, is usually in the centre of the flower. It has three parts:

the stigma, the sticky top that receives pollen;
the style, a tube joining the stigma to the ovary;
the ovary, the swollen base. Inside it are ovules, which contain the female sex cells (egg cells).

After fertilisation, each ovule becomes a seed and the ovary becomes the fruit.

Summary table

Part	Male, female or neither?	Job
Flower stalk (pedicel)	Neither	Holds the flower and attaches it to the branch
Sepals (calyx)	Neither	Protect the bud
Petals (corolla)	Neither	Attract pollinators with colour, scent and nectar
Anther	Male	Makes pollen
Filament	Male	Holds up the anther
Stigma	Female	Receives pollen; it is sticky
Style	Female	Joins the stigma to the ovary
Ovary	Female	Holds the ovules; becomes the fruit
Ovule	Female	Contains the egg cell; becomes the seed

Activity: take a flower apart

With your teacher, collect a large flower such as a hibiscus. Carefully remove the sepals, then the petals. Find the stamens and the pistil with a hand lens. Your teacher can cut the ovary in half with a blade so you can see the tiny ovules. Draw the flower and label it, using a ruler for straight label lines that do not cross. Wash your hands afterwards.

Tip

Stamen has "men" in it, so it is the male part. Stigma is sticky, so pollen sticks to it. And the ovary holds the ovules, the way a mother keeps her babies safe.

✦

Try it yourself

Which part of a flower makes pollen?
Name the three parts of the pistil.
What is the job of the sepals?
Why do maize flowers not need big, bright petals?
Which part of the flower becomes a seed?

Answers

The anther.
Stigma, style and ovary.
They protect the flower while it is still a bud.
Maize is pollinated by the wind, so it does not need to attract insects or birds.
The ovule.

Quick check

Keza finds tiny tips covered in yellow dust in the middle of a hibiscus flower. Which part of the flower makes this yellow dust (pollen)?

What you learned today

A complete flower has sepals, petals, stamens and a pistil.
The stamen (anther + filament) is male and makes pollen; the pistil or carpel (stigma + style + ovary) is female.
Ovules become seeds, and the ovary becomes the fruit.

Sources and credits

Natural Sciences Grade 7, Chapter 3: Sexual reproduction (3.1 Reproduction in angiosperms), by Siyavula Education, Siyavula, CC BY 3.0, adapted by Ganzaa.
Mature flower diagram, by Mariana Ruiz (LadyofHats), Wikimedia Commons, Public domain, used unchanged.

The exercises (Try it yourself and the practice questions) are written by Ganzaa.

1A complete flower

2The outer parts

3The male part: the stamen

4The female part: the pistil (carpel)

5Summary table

6Activity: take a flower apart