Flower Lab
Before completing the dissection read all of the packet directions, color the flower, answer the questions, and
review the diagram on double fertilization.
Dissect at least one flower. Draw and label the parts indicated below. You may wish to use class
texts and/or internet resources to help you learn about flower parts.
Draw the complete flower:
# of Petals ________ Attach one here.
# of Sepals_____ Attach one here.
# of Stamens_____ Attach one here. Label the
anther and filament. Draw it larger if it is too
small to properly label.
# of Pistils____ Attach one here. Label the
stigma, style, and ovary. Draw it larger if it is
too small to properly label.
Describe the flower you have just dissected by
circling one of each of the pair of terms
below:
Monocot or Dicot
Complete (All flower parts) or
Perfect (Both sexual parts) or
Incomplete
Imperfect
Regular (All petals and sepals are the same) or
Irregular
Review all the material in this packet and then complete a lab write-up to include the following:
Describe how flowers represented an major evolutionary step forward for plants. What is the
difference between pollination and fertilization? Describe the process of fertilization in angiosperms,
include the phrase ‘double fertilization’ and why it is an advantage for an angiosperm.
Flower Structure and Reproduction color page
Name______________________
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Name_______________________
Answer the following after reading the directions for and completing the Flower
Structure and Reproduction color page:
1. What is an angiosperm?
2. The flower attaches to what part of the plant?
3. Why are flowers brightly colored?
4. Name two mammals that might pollinate a plant.
5. If the petals of a flower are reduced or absent, how is the plant pollinated?
6. The female reproductive structures are called the:
7. Name the three parts of the pistil:
8. Where are the ovules stored?
9. Name the two parts of the stamen:
10. Describe sexual reproduction in plants.
11. The ovary develops into what structure?
12. Define fruit.
13. Some flowers are not brightly colored at all, but have a very pungent odor that smells like
rotting meat. How do you think these flowers are pollinated?
14. In many flowers, the pistils and stamens reach maturity at different times. Considering what
you know about pollination, why would this be an advantage to the plant?
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Complete this sheet only after you have reviewed all information
in the packet.
Flower Vocabulary Self-Test
Name ______________________
Multiple choice questions - place the letter of the best answer in the blank beside
the question number.
_______ 1. Flowers are composed of modified
.
A. leaves B. branches C. stems D. none of these
_______ 2. The female organ of a flower
.
A. stamen B. pistil C. anther D. none of these
_______ 3. Structures that protect the flower before blooming
.
A. petals B. pistils C. stamens D. none of these
_______ 4. The joining of sperm and egg in an ovule
.
A. pollination B. fertilization C. germination D. none of these
_______ 5. When a seed begins to grow into a new plant
.
A. pollination B. fertilization C. germination D. none of these
_______ 6. A ripened ovary with seeds
.
A. fruit B. pollen C. cotyledon D. none of these
True-false questions, use a plus (+) if the statement is true or a zero (O) if the
statement is false.
_______ 7. The puropose of a flower is to reproduce.
_______ 8. Self-pollination transfers pollen from one plant to another of the same
species.
_______ 9. Before fertilization can occur, the pollen grain on the stigma has to
form a pollen tube.
_______ 10. Each pollen grain contains three sperm nuclei.
_______ 11. Seeds can be dispersed by animals.
_______ 12. Cotyledons provide food for a new plant until the plant can grow its
leaves.
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Flower Structure and Reproduction Color Page Directions
Flowers are the plant's reproductive structures. Angiosperms are types of plants that bear fruits
and flowers. Flowers are usually both male and female, and are brightly colored to attract
insects to help them carry pollen used for sexual reproduction. Not all flowers are colorful,
though. These flowers usually use the wind for pollination.
Parts of the Flower
The receptacle is the part of the branch on which a flower forms. Color the receptacle (B) brown.
Sepals are leaf like structures that surround and protect the flower before it blooms. Color the
sepals (C) green. Petals are the colorful part of the flower that attracts insects and even other
small animals, such as mice, birds, and bats. Color the petals (D) a bright color of your choice.
All flowering plants have flowers, but some are not brightly colored. The petals of these flowers
are reduced or absent and the plant relies on the wind or water for pollination.
The flower has both male and female reproductive parts. The female reproductive structures are
called carpels. In most flowers, the carpels are fused together to form a pistil. Color the pistil (P)
pink. The pistil has three parts, which can be seen, in the box labeled "pistil". The stigma at the
top is often sticky and is where the pollen attaches. Color the stigma (J) purple. The style is the
long tube that attaches the stigma to the ovary. Sperm from the pollen will travel down this tube
to the ovules. The ovules, or eggs, are stored in the ovary until they are fertilized. Plants can
only fertilize eggs of the same species. Special chemicals prevent sperm from fertilizing the
eggs of flowers that are not the same kind. Color the style (K) red, and the ovary (L) pink. Color
the ovules (O) black.
The male reproductive structures are called the stamens. Color the stamens (H) blue. Each
stamen consists of an anther (A), which produces pollen, and a filament (F), which supports the
anther. In the box labeled "stamen" color the anther dark blue, and the filament light blue. Pollen
produced by the anther is carried by insects or other animals to the pistil of another flower where
it may fertilize the eggs.
The other flowers in the picture follow the same plan, although they come in many different
colors and styles. Color each of the flowers according to the colors above (blue for stamen, pink
for pistil, bright colors for the petals. etc.). Note that in some of the flowers, not all the structures
are visible.
Plant Reproduction
Sexual reproduction in plants occurs when the pollen from an anther is transferred to the stigma.
Plants can fertilize themselves: called self-fertilization. Self-fertilization occurs when the pollen
from an anther fertilizes the eggs on the same flower. Cross-fertilization occurs when the pollen
is transferred to the stigma of an entirely different plant.
When the ovules are fertilized, they will develop into seeds. The petals of the flower fall off
leaving only the ovary behind, which will develop into a fruit. There are many different kinds of
fruits, including apples and oranges and peaches. A fruit is any structure that encloses and
protects a seed, so fruits are also "helicopters" and acorns, and bean pods. When you eat a
fruit, you are actually eating the ovary of the flower.
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Flower Pollination and Double Fertilization
Flowers contain the structures necessary for sexual reproduction. The male component, or stamen,
consists of a thin stalk called the filament, capped by the anther. The female component, the carpel,
includes the stigma, a sticky surface that catches pollen; the ovary, which contains the ovule and
embryo sac with its egg; and the style, a tube that connects the stigma and ovary (A). Pollen is
produced in the anther (B), and is released when mature (C). Each mature pollen grain contains two
sperm cells. In self-pollinating plants, the pollen lands on the stigma of the same flower, but in crosspollinating plants—the majority of plants—the pollen is carried by wind, water, insects, or small
animals to another flower. If the pollen attaches to the stigma of a flower from the same species, the
pollen produces a pollen tube, which grows down the neck of the style, transporting the sperm to the
ovule (D). Within the embryo sac of the ovule, one sperm cell fertilizes the egg, which develops into
a seed. The second sperm cell unites with two cells in the embryo sac called polar nuclei, and this
results in the development of the endosperm, the starchy food that feeds the developing seed. The
ovary enlarges (E) and becomes a fruit.
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Flower Anatomy
The Flower:
The flower is the reproductive unit of some plants (angiosperms). Parts of the flower include petals, sepals, one or more carpels
(the female reproductive organs), and stamens (the male reproductive organs).
The Female Reproductive Organs:
The pistil is the collective term for the carpel(s). Each carpel includes an ovary (where the ovules are produced;
ovules are the female reproductive cells, the eggs), a style (a tube on top of the ovary), and a stigma (which
receives the pollen during fertilization).
The Male Reproductive Organs:
Stamens are the male reproductive parts of flowers. A stamen consists of an anther (which produces pollen) and a
filament. The pollen consists of the male reproductive cells; they fertilize ovules.
Fertilization:
Pollen must fertilize an ovule to produce a viable seed. This process is called pollination, and is often aided by
animals like bees, which fly from flower to flower collecting sweet nectar. As they visit flowers, they spread pollen
around, depositing it on some stigmas. After a male's pollen grains have landed on the stigma during fertilization,
pollen tubes develop within the style, burrowing down to the ovary, where the sperm fertilizes an ovum (an egg
cell), in the ovule. After fertilization, the ovule develops into a seed in the ovary.
Types of Flowers:
Some flowers (called perfect flowers) have both male and female reproductive organs; some flowers (called
imperfect flowers) have only male reproductive organs or only female reproductive organs. Some plants have both
male and female flowers, while other have males on one plant and females on another. Complete flowers have
stamens, a pistil, petals, and sepals. Incomplete flowers lack one of these parts.
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Flowers are composed of modified leaves. Each floral structure represents a
different modification of a leaf. Not all flowers have the same parts, but male
and/or female structures are essential.
Flower Parts Key:
Receptacle: (#6)


The swollen tip of the stalk (#7) supporting the
flower.
You might think of a flower as a highly modified
branch, the flower parts being highly modified
leaves.
Sepal: (#5)




The outer floral structure.
Most sepals are green, but they can be brightly colored like the petals.
Sepals protect the flower before blooming.
All the sepals together are called the calyx.
Petal: (#4)



Attached just inside the sepals.
Usually brightly colored to attract pollinators.
All the petals together are called the corolla.
Pistil: the female organ.




Stigma (#1), the open top of the pistil. It is sticky so it can trap pollen grains.
Style (#2), the hollow tube leading to the ovary.
Ovary (#3), composed of fused ovules.
Ovules, each ovule produces one egg cell.
Stamen: the male organ.


Anther (#9), produces pollen grains which contain sperm cells.
Filament (#8), supports the anther.
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