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Petal

life science Maturity 13-18 Next article →

Petals are special parts of a flower. They are actually modified leaves. All the petals in one flower are called the corolla.

Petals usually sit in a ring around the middle of the flower. This ring is part of the perianth. The perianth also includes the calyx, which is made of sepals. Sepals are the leaves that sit just below the petals.

Mature flower diagram
Mature flower diagram

In some plants, like tulips, the petals and sepals look almost the same. We call these parts tepals. When these tepals look like petals, we say they are petaloid.

20140226Narcissus2
20140226Narcissus2

Petals can grow in many different ways. Sometimes the petals are separate from each other. This is called being apopetalous. Other times, the petals are joined together. This is called being gamopetalous.

Perianth morphology fusion aposepalous apopetalous
Perianth morphology fusion aposepalous apopetalous

When they join, they can form a long corolla tube.

2007 brugmansia aurea
2007 brugmansia aurea

Petals also have different shapes. Some flowers are actinomorphic, which means they look the same all around. Others are zygomorphic. This means they only have symmetry if you split them down one side.

White pea flower
White pea flower

You can see zygomorphic flowers in orchids or the pea family.

Scientists have studied how these shapes work for a long time. Charles Darwin was a famous scientist who studied them. He looked at how long corolla tubes and shapes began.

2007 brugmansia aurea
2007 brugmansia aurea

He had a theory about how these parts first appeared. We also know how petals are built using the ABC model. This model shows that petals, sepals, and other parts are all modified versions of each other. It seems that the way to make petals evolved only a few times in history.

Mature flower diagram
Mature flower diagram

There are many interesting facts about petal numbers and types. Most eudicot flowers have four or five petals. Monocot flowers often have three or six petals.

20140226Narcissus2
20140226Narcissus2

Some flowers have parts that look like a leaf blade and a stem. The wide part is called the blade. The narrow part is called the claw.

Some plants like the rose have very clear petals. Other plants like grasses are different. Grasses are often apetalous, which means they have no petals at all.

Petals have a very important job called pollination. This helps plants make new seeds. Many flowers use bright colors to attract animals. Some flowers have nectar guides. These are marks that lead pollinators to food.

White pea flower
White pea flower

Some marks are in ultraviolet light. Humans cannot see them, but bees can.

White pea flower
White pea flower

Other flowers use smells to help. Roses smell sweet to humans. Some flowers smell like rotting meat to attract flies.

Some plants even use color to talk to birds. The tree fuchsia turns from green to red to tell birds it is ready.

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🖼️ Images & Media (8)
File:Mature flower diagram.svg
Mature flower diagram.svg
File:Perianth morphology fusion aposepalous apopetalous.png
Perianth morphology fusion aposepalous...
File:2007 brugmansia aurea.jpg
2007 brugmansia aurea.jpg
File:Pelargonium peltatum 9245s.jpg
Pelargonium peltatum 9245s.jpg
File:Geranium incanum 9156s.jpg
Geranium incanum 9156s.jpg
File:White pea flower.jpg
White pea flower.jpg
File:20140226Narcissus2.jpg
20140226Narcissus2.jpg
File:使君子Combretum indicum 20210523080843 01.jpg
使君子Combretum indicum 20210523080843 01.jpg
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