FOCUS: Flowers come in all shapes and sizes, but they all serve the same function: to produce seeds. We’ll look at the insides of flowers to see how seeds develop and compare different kinds of flowers and their structures. To make seeds, flowers need to be pollinated. Some do this with the help of the wind and others with the help of animals, like hummingbirds, moths, beetles, and especially bees.
Objective: To begin to explore and ask questions about flowers and fruit.
Give each small group of children a variety of flowers, and ask children to talk about what they notice about the different flowers.
Materials: an assortment of flowers, magnifying lenses
Objective: To investigate a flower’s structure, sorting the parts and looking for patterns of similarities and differences.
Give each pair of children a simple flower, such as a Peruvian lily (Alstroemeria), daffodil, or tulip, and a magnifying lens. It is helpful if everyone has the same kind of flower to begin with. Once they have learned to recognize the parts of a flower, you can introduce more variations and more challenging flowers (petunias, pansies).
First, ask the children to observe their flowers and share things they notice and wonder about, making note of their questions. Have the children turn the flower upside down. Starting with the outermost layer, have them remove the parts in each concentric ring, putting similar parts together. (To see which is the outermost ring, look at a bud, or gently gather the petals of an open flower together as they would have been in bud, to see which are on the outside.) As they dissect their flowers, name and discuss each flower part and its function. Provide older children with four index cards – labeled Sepals, Petals, Stamens, Pistil(s) – on which to place flower parts as they remove them.
Stem – holds up the flower
Sepals (outermost ring of flower parts) – protect the bud; usually green but can be the same color as petals
Petals (next ring of flower parts) – attract pollinators, often giving them a landing place; often colorful, may also make scent and/or nectar
Stamens (next ring of flower parts) – produce and hold the pollen, made up of a filament (the stem), anther (the canoe-shaped structure at the tip that holds the pollen), and pollen (the tiny grains on the anthers)
Pistil(s) (at center, may be one or more) – act as catcher for pollen, container for the ovule(s). Pistil is made up of the vase-like ovary, the stem-like style, and the sticky stigma at the top of the style
Ovules (found inside the ovary, often look like tiny white beads) – become the seeds when fertilized by pollen that has landed on the stigma
- Count the number of parts. How many are there of each part? Do they notice a pattern? (Lily Family flowers have three sepals and three petals, six stamens, a three-lobed stigma and three-sectioned ovary – all parts in threes or multiples of three.)
- Look for color patterns such as lines, spots, or stripes on petals; find pollen grains and observe their color.
- Tear or cut open the base of the pistil to find the ovules (use fingernails, or an adult may do this with a small knife). It is helpful to open some lengthwise and some crosswise. What will each ovule eventually become? (A seed.)
- Pass around one or more other flowers and compare the flower parts in the different flowers.
Materials: for each child or pair of children: magnifying lens; a Peruvian lily (Alstroemeria), daffodil, or tulip; other flowers like apple, violets, pansies, marigolds, petunias, snowdrops, geraniums, marsh marigolds; for older children, four large index cards labeled Sepals, Petals, Stamens, and Pistil(s); small knives for leaders, Flower Parts diagram.
BUILD A FLOWER
Objective: To use a model to review the parts of a flower and their arrangement.
Have the children work in small groups, and give each team a felt board and felt flower parts. Review each of the parts learned in the previous activity while dissecting real flowers. Have the children use their flower parts to create a felt model of a flower. Hold up their felt boards for all to see. Did all groups construct their models in the same way? Did some put petals and sepals below the ovary and others put them above? Compare to a Flower Parts diagram and point out that ovaries can be above or below the sepals and petals in different kinds of flowers.
Now the leader, or a child from each team, gets a bee puppet, which collects pollen from one felt flower and buzzes over to another flower, dropping it off on the pistil and picking up some of that flower’s pollen to take on to the next flower she visits. Make sure that every felt board flower gets pollinated. As each flower receives pollen, have a pollen grain travel down the style and meet the ovules; then the children change the ovules into brown or black seeds. Once the seeds are developing, does the flower need pollinators anymore? Now that their job is done, what happens to sepals, petals, and stamens? (They usually fall off, so children can remove them from their model.) What happens to the pistil as the seeds grow? (Gets bigger.)
Materials: for each group: felt board, felt flower parts, honeybee puppet, Flower Parts diagram.
FRUIT FROM A FLOWER
Objective: To observe how flowers become fruits containing seeds, and to look for remnants of the flower parts.
Pass around and then cut open several fruits or seed-containing “vegetables” (which in botanical language are fruits). Notice how the ovary of the flower swells to become the seed container. Look for seeds on the inside and remnants of flower parts on the outside. Sepals and shriveled remains of pistils can often be found.
- Sweet (green, orange, yellow) pepper or eggplant: the sepals can be seen at the stem end of the pepper or eggplant, and the tiny remnants of the pistil at the other end. (Botanically, a superior ovary.)
- Apple, pear, zucchini, pomegranate: the fruit forms beneath the flower so all the remnants of flower parts are found on the far end of the fruit. (Botanically, an inferior ovary.)
Materials: fruits such as green pepper or eggplant, apple, pear, zucchini, pomegranate; knife for adult leader to use, cutting board or paper plate.
PUPPET SHOW “All the Buzz about Flowers”
Objective: To learn why plants have flower, and how different flowers are pollinated.
Perform the puppet show or have a group of children perform it for the class. Afterward, ask questions to review key details and vocabulary in the story. Why do some flowers have showy petals and sweet nectar? (To attract bees.) Why do they need bees? (To bring them pollen from another flower.) Why do flowers need pollen from another flower? (To fertilize the ovules so they can become seeds.) Why doesn’t the grass plant need to attract bees? (Their pollen is light-weight and can be carried by the wind.) How does the chickadee help the flower? (By dropping some of the seeds in places where they can grow.)
Materials: puppets, script, props, stage.
Objective: To investigate flowers on the school grounds, looking for evidence of the kind of pollinator they attract.
Take a tour of your schoolyard to find flowers. Be sure to look at the trees, shrubs, and lawns (for very small flowers), as well as gardens and wild edges.
Look for different stages in the life cycle of flowers:
- in bud
- finishing blooming
- developing seeds
Look for evidence of flowers that are wind-pollinated:
- green, brown, or dull-colored flowers
- very fine, powdery pollen that comes off when you shake the flower
Look for ways flowers attract pollinators, such as:
- center of flower is a different color from the petals
- bee guides: spots, dots that guide insects to the center of the flower
- places where the flower might hold nectar
- brightly colored petals and/or sepals
- fragrances, either pleasant or unpleasant
Look for pollinators. Do you see insects visiting any flowers?
Materials: Flower Tour cards, clipboards, magnifying lenses. If you have a schoolyard with no flowers, bring in as many kinds as you can; put containers of them scattered around the outdoor area, so students can visit and examine them.
JOURNAL ACTIVITY – Draw a Flower
Objective: To make close observations of a single flower, looking for evidence about how it is pollinated.
Have the children choose one of the flowers they found to study closely. If there are plenty, they should pick one to see it better. Have them draw the flower, answering the questions as they study it closely.
Draw a Flower
Choose a flower to draw. Draw the whole flower, from the side and from above, then draw the parts as you take it apart. Answer these questions as you study your flower:
- Does the flower have sepals, petals, stamens, and pistil(s)? How many of each? Some flowers don’t have all of these parts.
- Are the petals separate or joined in a tube? What about the sepals? (Look carefully! They may be joined at the bottom and separate at the top.)
- What kind of symmetry does your flower have? Like a wheel (radial), or with right and left sides the same (bilateral)?
- How do you think this flower is pollinated? What makes you think so?
Materials: journals or paper and clipboards, pencils, colored pencils, magnifying lenses; if needed: additional flowers in jars, pots, or flats to place around the schoolyard.
Objective: To model the close connection between type of pollinator and flower characteristics.
Give each child a large picture card showing either a pollinator or a flower. Have the children make two lines, with pollinators and flowers separated from each other. The Pollinator now reads its clue, which describes the characteristics of flowers it pollinates. The Flower waves its sign to attract its pollinator. The Pollinators run to the appropriate Flower.
Hummingbird and bee balm (Hummingbird: I like a bright red, tube-like flower with sweet nectar inside.)
Sphinx moth and evening primrose (Moth: I like pale-colored flowers that open at night, with sweet-smelling nectar to drink.)
Wind and grass or birch (Wind: I can carry tiny pollen grains. Some will land on just the right kind of flower.)
Carrion fly and trillium (Carrion fly: I need to lay my eggs in rotting dead animals, so I look for dark red, stinky things.)
Honeybee and clover (Honeybee: My tongue is not very long, so I visit short tube-like flowers for nectar and pollen.)
Bumblebee and snapdragon (Bumblebee: I’m big, so I can push my way into flowers that smaller bees can’t get into.)
Why do flowers need pollinators? (To bring them pollen from another flower so they can form seeds that combine traits of the parents.)
Materials: Pollinator card or Flower card for each child.
UPPER GRADES CHALLENGE: Flower Families (Grades 5-6)
Objective: To compare the number, shapes, and position of flower parts, looking for patterns of similarities and differences in four flower families.
Set out several flowers from the Lily, Rose, Violet, and Aster families at stations. Have students work with a partner to examine each of the flowers in turn, observing the parts and their shapes and counting the numbers of sepals, petals, stamens, and pistils on each one. Then compare them to their Flower Families sheet with diagrams of each family and the famous plants that belong to it. Ask the students to try to decide, based on their observations, which flower(s) belong in each of the families. Ask students what types of symmetry they can see in the different flowers. (Bilateral in violet, radial in others.) Which flower might produce the most pollen? Can you see where the seeds will be formed? Are the sepals and petals different or similar? How does each attract pollinators? Discuss the ornamental, edible, or otherwise useful members of each family.
Lily Family: three sepals and three petals, all identical in size and color. Six stamens (some may lack anthers), a three-part pistil.
Examples: lily, tulip, hyacinth, daffodil, lily of the valley, onion.
Violet Family: five sepals, five petals (bottom petal longer than other petals), five stamens, pistil with thickened head and short beak.
Examples: violet, pansy, johnny-jump-up.
Rose Family: five sepals, five petals, numerous stamens (usually multiples of five), usually several pistils (five in apples).
Examples: rose, apple, strawberry, raspberry.
Aster Family: flowers made up of many smaller flowers growing together on a disk, each producing one seed; each tiny flower has five petals fused into a tube, five stamens fused together into a tube around the pistil, one pistil with two stigmas.
Examples: dandelion, daisy, sunflower, goldenrod, aster.
Materials: flowers from the four families (Lily, Rose, Violet, Aster), paper, pencils, clipboards, magnifying lenses, Flower Families sheet for each team.
Objective: To review and share some thoughts about flowers.
Ask the children, “What is something you learned about flowers today?” Challenge the group to think of as many different things as possible.
Optional: Give a paper cutout of a flower petal to each child and have them write one thing they learned about flowers, then use the petals to make a big classroom flower display. For younger children, adults can write for the children.
Materials: optional: colored paper, pencils, tape, circle for the flower center, poster board.
A STEP BEYOND
Flowers and Vegetables: Have children look at vegetable plants in bloom, studying their flowers and placing them in these important flower families: Grass, Squash, Bean, Mint, Parsley, Rose, Nightshade. What are the characteristics of these flower families?