What Is the Purpose of a Flower

Learning Objectives | National Science Education Standards
Background Information | Pre-Visit Activities
Inquiry Activities at the Garden | Suggested Galleries
Post-Visit Activities | Resources

Learning Objectives

• Flowers are the reproductive part of the plants.
• The main purpose of flowers is to make seeds.
• The key parts of the flower are sepal, petal, stamen, pistil, and ovary.
• Part of a flower (the ovary) matures into a fruit, which contains the seeds.
• Anything with seeds inside is botanically a fruit.
• Seeds make new plants.
• Seeds are transported to new locations by many means, including wind, water, and animals.

National Science Education Standards

• Understand the characteristics of organisms.
• Understand the life cycles of organisms.
• Understand the process of scientific inquiry.

Background Information

Flowers make pollen, attract pollinators, produce fruit, and make seeds. Despite differences in appearance, most flowers have a similar structure:

• Sepals protect the bud and support the flower.
• Petals attract pollinators and provide a platform to support them.
• Stamens produce the pollen grains.
• Pollen contains male sperm cells, which join with the eggs in the ovules to form seeds.
• The pistil is where pollen is deposited on the stigma and enters the ovary.
• The ovary contains the ovules and is where the seeds develop, and mature into fruit.
• Ovules, containing female egg cells, mature into seeds when fertilized by male sperm cells.

Pollination occurs when pollen lands on the sticky top of the pistil called the stigma. The pollen forms a pollen tube through the pistil to the ovary, where male sperm cells join with female egg cells inside the ovules in a process called fertilization.

The shape, color, and fragrance of a flower provide clues as to the size and shape of its pollinator. Tube-shaped flowers such as honeysuckle are typically pollinated by animals with a long beak, proboscis, or tongue.

Fragrant, showy flowers attract pollinators. Flowers that use wind to disperse pollen tend to be small and lack fragrance.

Once fertilized, the ovary matures into a fruit, which contains seeds. The fruit protects and houses the seeds. Fleshy, sweet fruit is eaten by animals that transport and deposit the seeds in a new location. Fruit that is small, dry, and light —such as fluffy dandelion and cattails, or winged maple fruits—is transported through the air. Some seeds, such as coconut, are transported by water. By moving away from the parent plant, seeds avoid competing for water, light, minerals, and space.

Pre-Visit Activities

• Draw a flower from the imagination. Then, using a real flower as a model, make a second sketch, observing and recording its parts. How does this sketch differ from the one of the imaginary flower?

Inquiry Activities at the Garden

• Look in the trees for fruit, on the ground for seeds, and all around for flowers to see the amazing diversity among plants. Remind students not to pick or remove any plant parts. They can touch and examine them, but they should then leave them for other visitors to discover.
• Use a hand lens to observe flower parts such as the stamen, pistil, and ovary. Explore dry fruit found on the ground, such as spiky, brown sweet gumballs or winged maple arils. Look for seeds inside, or signs of where they were.
• Search for and then draw a flower, a fruit, and a seed. Draw an arrow showing the sequence of transformation.
• Sketch a flower, label the parts, then describe the function of each part.
• Make a list of the new types of fruit discovered.
• “Stake out” an area with lots of flowers. Try to observe a pollinator in action. Record its behavior and count the number of flowers it visits.
• Select a flower and invent a pollinator species uniquely adapted to pollinate it. Draw the pollinator and describe its unique adaptations to carry pollen from one flower to another.

Suggested Galleries

• The Hecksher Foundation for Children’s Wonder Gallery
• Arthur Hays and Iphigene Ochs Sulzberger Meadow Gallery
• Meadow Maze
• The Vincent Astor Foundation Sun, Dirt and Water Gallery
• The Con Edison Pond Gallery

Post-Visit Activities

• Create a species name for the invented pollinator, reflecting its unique adaptations.
• Write a story about what would happen to the plant if its pollinator went extinct. What parts of the plant’s life cycle would be interrupted?
• Invent and draw a seed with a unique means of transportation. Describe its characteristics (hooks, barbs, wings, tassels,) to classmates; see if they can determine how it is transported.

Resources

Heller, Ruth. 1983 The Reason for a Flower. New York: Penguin Putnam.

Cox, Rosamund Kidman, and Barbara Cork. 1990. Flowers. Usborne First Nature series. London: Usborne Publishing.

Jeunesse, Gallimard, Claude Delafosse, and René Mettler. 1991. Flowers. New York: Scholastic.