Lab ____: The Reproductive Structures in a Flower
Lab skills: 1, 3, 6, 8, 13, 18, 19, 26, 28
Background: Flowers are the reproductive organs of angiosperms, or flowering plants.
Flowers vary in size, color and arrangement. All flowers, regardless of variety, have the
function of seed formation and are responsible for the production of more plants. Flowers
contain both non-reproductive and reproductive structures.
In this investigation you will examine a flower and identify its non-reproductive parts and its reproductive parts. You will
also observe the male and female sex cells produced by a flower underneath a microscope.
Hypothesis: If flowers are reproductive structures then there must be male parts and / or female parts within them.
Procedure:
Part A – Observing the External Anatomy of a Flower
1. Refer to Figure 1 as you examine the flower. Identify the
receptacle, or structure to which all other flower parts are
attached. Note the sepals, which are small, leaf-like
structures above the receptacle. All of the sepals together
are called the calyx. Observe the brightly colored petals
inside the calyx. All of the petals together are called the
corolla. These structures make up the non-reproductive
structures of a flower.
2. Record the number and color of both the sepals and the
petals in the first table in your results section.
Part B – Reproductive Structures of a Flower
3. Using Figure 2 identify the male reproductive structures, or
stamens. Each stamen consists of an anther and a filament.
4. Identify the female reproductive structure, or pistil. Each pistil
consists of an ovary, a stigma, and a style.
5. Sketch the flower you observed on your answer sheet.
Label the stamen, anther, filament, pistil, ovary, stigma and
style.
6. With scissors or forceps carefully remove the petals from the
flower. Make sure you do not damage any reproductive
structures.
7. With forceps, remove the stamens and place them on a sheet of
unlined white paper.
Flower Reproductive Structures Lab
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8. Use a hand lens to get a close look at the male reproductive structures of the flower. Sketch what you see and
label the pollen, anther, and filament on your stamen drawing on your answer sheet. Set the stamens aside for
use in Part C.
9. Carefully remove the pistil using a razor. Cut the ovary in
half as its widest part as shown in Figure 3.
10. Observe the inside of the ovary. Note the number and
arrangement of the ovary chambers. The white, oval
objects inside the chambers are the ovules (or eggs).
11. Sketch a cross section of the ovary showing the
number and arrangement of the chambers on your
answer sheet. Label the ovules, ovary walls and
chambers. Set the pistil aside for Part C.
Part C – The Gametes of a Flower
12. With forceps, remove an ovule from the dissected ovary. Make a wet-mount slide of the ovule.
13. Observe the slide at low power and calculate the magnification. Sketch what the ovule looks like in your results
section and record the magnification at which you viewed it.
14. Gently brush an anther from one of the stamens across the stigma of the pistil. With a hand lens look for pollen grains
that may have stuck to the stigma.
15. Make a wet-mount slide of pollen and observe it at high power. Sketch what the pollen looks like in your results
section and record the magnification at which you viewed it.
Analysis:
A. List the function of each of the following parts and note whether the parts comprise the pistil or the stamen.
1 – anther 2 – filament 3 – ovary 4 – ovule 5 – pollen 6 – stigma 7 – style
B. Why does a flower have more pollen grains than ovules?
C. Explain why heavy rainfall on a fruit orchard in the spring might result in a poor fruit yield in the fall.
D. For what biological reason might farmers object to people picking apple blossoms during the apple blossom season?
E. Flowers that are pollinated by the wind have smaller petals and sepals than flowers that are pollinated by insects or
animals. Why are small petals and sepals an advantage to these flowers?
F. Why do flowers that are pollinated by insects have large, brightly colored petals?
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Name(s) __________________________________________________________________________ Period ________
Reproductive Structures in a Flower Lab Results
Flower common
name
Flower classification
name
Labeled sketch of a flower
Number of
sepals
Color of
sepals
Number of
petals
Color of
petals
Labeled sketch of the male reproductive
parts of a flower
Labeled sketch of the female reproductive
parts of a flower
Ovules @ low power
Pollen @ high power
Magnification: ___________________
Magnification: ___________________
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Part A…
Observe sepals
and petals here!
Part B…
Observe the
flower here!
Flower Reproductive Structures Lab
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Part B…
Observe the male
reproductive
flower parts here!
Part B…
Observe the
female flower
parts here!
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Part C…
Observe the
ovules here!
Part C…
Observe the
pollen grains here!
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