Lab 8 : Flower Dissection: A Perfect Flower
Materials: Perfect Flowers (Lily, petunia, hibiscus, snapdragon, geranium), scissors or razor
blade, hand lens, tweezers and a dissecting scope (optional).
Pairs. You can do this lab in pairs. Both people can have the same data, but only if they work
together. Each person must still have the answers to the questions in your own words.
Do This!
Follow the procedures below to dissect a perfect flower. Be sure to sketch and describe the
physical observations you make about this flower and the parts.
Flower Dissection:
Step 1: Obtain a large flower and examine it. Using the diagram provided as a reference,
compare your flower to the diagram. Are there any features that stand out? Sketch a picture of
your flower in your lab notebook. Label the structures that can bee seen.
Step 2: Look for the sepals of your flower. The sepals are typically on the outside of the flower,
often green, sometimes small and withered, sometimes as large as the petals. Describe the sepals
in your notebook. Are they small or large in comparison to the petals?
Step 3: The petals compose the next "ring" of flower structures. Examine the texture and color of
the petals using a magnifying glass. If your flower is colored, pinch a small piece of a petal
between your fingers and examine the colorful pigment released. Write your observations on
your lab notebook.
Step 4: Carefully pull back the petals of the flower to expose the stamens. If necessary, use a
razor blade or scalpel to help expose the internal structures. Count the number of stamens; record
this number in your lab notebook.
Step 5: The stamens each have an anther at the top of the filament shaft. Pollen grains are
released from the anther. Examine the anther using a magnifying glass and touch the tip of your
finger to the anther. What happened? Copy your observations in your lab notebook.
Step 6: Gently separate the flower from the green sepals and base to locate the carpel. Notice that
the carpel has three parts: a sticky stigma at the top, a long shaft called a style, and an ovary at the
bottom. Cut open the carpel to see the ovary.
Step 7: Use a probe or blade to cut into the ovary lengthwise. Gently open the ovary. Inside are
one or more ovules. Each ovule contains an egg.
Answer these in your lab notebook! (use good complete sentences, underline key part of answer).
1. Which does your flower produce in greater numbers: ovules or pollen grains? Explain
why this would be important in terms of reproductive success.
2. Why do you suppose the petals of flowers are so colorful, fragrant, uniquely shaped?
3. How is the stigma of your flower adapted to capture and hold pollen?
4. How does the “sperm” get to the egg in this type of plant?
5. Why do you think this type of flower is called perfect?