Flowers
The flower is one of nature’s most vibrant and varied displays of a common structure. They are
also the sex organs of the plant. Flowers contain both male and female organs. The female organs are
collectively called the Pistil. The male organs of the plant are called the Stamen.
Female Organs
Ovary – Where the ova is held
Ova – Egg. Becomes the seed after fertilization
Pistil – All of the female organs of the plant
Stigma – Pollen receptor. Has a sticky coating
to catch passing pollen grains.
Style – Long structure that has Stigma on top.
Male Organs
Stamen – the male reproductive organs of the
plant
Fliament – Support structure for the Anther
Anther – Produces pollen grains on the surface.
Pollen Grains – Contain the plant’s sperm.
Fertilization in Plants
Since plants can’t move, they needed to find a different way to fertilize the ova. They
found a way to use other organisms and things like wind to help in fertilization. These are the
steps to plant reproduction.
1) The sperm are produced inside of pollen grains. These pollen grains are on the top of
the anther. The ova are produced inside of the ovary.
2) Other organisms such as bees and hummingbirds or things such as wind carry the
pollen grains from the anther to the stigma of another plant. These things that move
the pollen grains are called Factors.
3) When a pollen grain lands on the stigma, it gets stuck on the sticky substance that
lies on the top of the stigma. When the pollen grain gets stuck a tube starts to open
in front of the pollen grain. This tube is called the Pollen Tube. The pollen tube will
continue all the way through the ovary.
4) Once in the ovary the pollen grain has opened letting out the sperm. The sperm then
fertilize the ova creating a zygote. That zygote will become the seed.
Dissecting Your Flower
When you dissect your flower please follow these instructions:
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Open the petals of the flower and observe all of the parts of the flower. Try to identify
which parts are which using your diagram. How many of each structure are there?
Look at how and where all of the parts are attached.
After you have looked at the intact flower, carefully remove some of the pedals.
Next remove a few stamens. Identify the anther and the filament.
Cut a cross section of the anther and observe how it looks on the inside.
Carefully remove the pistil. Observe the stigma and style.
Cut a cross section of the ovary to see what is inside.