plant groups - department of education and...

Lesson 18/20 More about classifying plants 1

Plant groups

In this lesson on plant groups, you will be investigating a system of

classifying plants that is used today.

What are the main plant groups?There are five groups of plants in the modern classification system.

They are:

• algae

• bryophytes

• pteridophytes

• gymnosperms

• angiosperms.

What features are used in plantclassification?

What features are used to classify plants?

The key below shows you some of the main groups of plants.

2 Living things

Are there roots and stems?

Are there seeds?

Are there flowers?bryophytes

angiosperms

plants

no yes

no yes

no yes

pteridophytes

gymnosperms

Are there leaves?

algae

no yes

Plant group key

Activity: What features are used in plant classification?

Make a list of the features used to classify plants.

__________________________________________________________

__________________________________________________________

__________________________________________________________

Plants are classified using structural features including roots, stems, leaves,

seeds and flowers.

A quick look at each plant group

The table on the next page contains a drawing and description of an

example from each plant group.


Activity: A quick look at each plant group

Use the key above to identify the group that matches each example.

Drawing Description Plant group

Lives in damp places,

often in water; simple

leaves but no roots,

stems or flowers

1 _________________

Lives in many

environments; leaves in

many shapes, roots to

absorb water and

minerals, seeds and

flowers for reproduction

2 _________________

Usually lives in damp,

shaded places; roots,

stems and leaves in

fronds but no flowers or

seeds

3 _________________

© State of New South Wales, Department

of Education and Training, 2004

4 Living things

Usually lives in water,

either floating or

attached to the bottom;

does not have roots,

stems or leaves

4 _________________

Lives in many

environments; needle-

shaped leaves, extensive

roots and stems but no

flowers

5 _________________



Check your response by going to the suggested answers section.

You have classified the major groups of plants now take a more detailed

look at the plant groups.

A more detailed look at plantgroup featuresIn this section, you will read about each of the main plant groups.

Then, there is a summary for you to complete at the end of this section.

Algae

Have you ever been to the seaside? All around the rock pools and even

in the water there are plants. These plants are called seaweeds.

There are a large number of different seaweeds. Seaweeds are plants that

belong in the group, algae.


Algae

© State of New South Wales, Department of Education and Training, 2004

Algae can be green, red or brown. Ulva is an example of a green algae.

It is sometimes called sea lettuce. Corallina is an example of a red

seaweed.

Look at the photograph and diagram of another type of algae in the

following pictures.

Hormosira sp


6 Living things

Hormosira is an example of brown algae. This plant is sometimes called

Neptune’s necklace. It lives in rock pools on the seashore.

Here is a drawing of Hormosira. It gives a more detailed view of this

plant.

Diagram of Hormosira


So far, you know that algae live in seawater. There are other types of

algae that live in freshwater ponds, rivers or just very wet places.

What makes algae different from other plants? Algae are different

because of what they do not have, rather than what they do have.

Algae do not have roots, stems or leaves.

Activity: Algae

Think back. Why are algae classified as plants?

__________________________________________________________

__________________________________________________________

Algae can make their own food. All the organisms that make their own food

are called plants.

However, algae are very simple. And there are animals that are very

similar to algae, except that they cannot make food. In the most recent

classification systems, algae and these animals that are similar to algae

are put into a kingdom of their own called the protists. Protistos is a

Greek word that means the very first. So protist is the kingdom for the

simplest organisms, including algae.


Bryophytes

Have you ever been in a damp dark forest? Did you notice the green flat

plants covering the forest floor? Have you noticed a bright green plant

that looks and feels like velvet growing in a dark and damp corner of

your garden? If you have, then you‘ve seen some examples of the group

of plants called bryophytes. Mosses and liverworts are bryophytes.

Bryo- means moss in Greek and -phyte means plant, so bryophytes are

plants that are like mosses.

So far you have learned that bryophytes are small plants that grow in

damp places on land. But what are the other features of mosses and

liverworts?

Mosses

The 'carpet' in the background of the photograph ‘Mosses on the forest

floor’ below is a moss. Compare the photograph with the diagram ‘Moss

plant’.

This will give you a better idea of some features of mosses.

Mosses on the forest floor

Source: © Jane West

spore capsule

simple leaves

attachment



The attachments on a moss are not roots. They do not absorb water and

minerals in the way that true roots do.

8 Living things

Liverworts

Below is a photograph of some liverworts growing with some moss.

Source: © Barbara Gurney

Liverworts are often found on the forest floor.

Compare the photograph and diagram of the Liverworts to get a better

idea of some features of liverworts.

spore capsule

simple flat leaves

Diagram of a liverwort



Did you notice tiny structures sticking out of the mosses and liverworts

in the photographs and drawings? These structures are spore capsules.

They contain tiny spores for reproduction.

Activity: Liverworts

Now answer these questions.

1 Do liverworts have roots? _________________________________

2 Do liverworts have flowers? _______________________________

3 Why are liverworts called bryophytes?

_______________________________________________________

_______________________________________________________


Pteridophytes (ferns)

Do you have any indoor plants? Many plants sold as house plants are

ferns. Common ferns include tree ferns, maidenhair ferns, fishbone ferns

and bracken.

Pteridophyte comes from two Greek words. Pteris means a fern and -

phyte means a plant.

Activity: Pteridophytes (ferns)

What is a pteridophyte?

___________________________________________________________

___________________________________________________________

A pteridophyte is a plant that is like a fern.

The leaves of pteridophytes often have a lacy appearance. This can be

seen in plants like the maidenhair fern. Fern leaves are called fronds.

10 Living things

Fern


And have you ever noticed the back of fern fronds? If you look closely,

you may see some little brown spots. These are spores. Ferns reproduce

by spores.

Look at the following photograph and find the spores. Then look back at

the photograph above. Can you identify spores in the photograph?

Spores on the back of a fern leaf

Source: © Jane West


The following diagram also shows some other features of pteridophytes.

spores for reproduction

roots absorb water and minerals

stems joining roots and leaves

frond (fern leaf)

A fishbone fern


Pteridophytes, or ferns, are found in many different locations or

environments. They need to be in places where there is a fair amount of

moisture so you will not find them in a desert! They have roots to absorb

water but they need moisture so that spores can move around for

reproduction.

Pteridophytes, or ferns, can be a pest in some areas. Ferns such as

bracken are sometimes called weeds. If you’ve ever had to dig out ferns

where they are a problem, then you will have noticed that the stems are

underground. One exception to this is the tree fern that is a very tall fern.

12 Living things

Tree fern


Gymnosperms

Have you ever noticed the features of a traditional real Christmas tree?

If you have, then you already know a lot about the group of plants called

gymnosperms. Gymnosperms include cycads, fir trees, pine trees,

cypress, spruce, ginkgo and redwoods.

In Greek, gymnosperm means “a plant with naked seeds". This is

because the seeds of a gymnosperm are not inside a fruit. Instead, a

gymnosperm has its seeds inside cones. When the cones open, the seeds

fall out.

You can see some of the main features of a gymnosperm in the following

drawing. It is a drawing of the most familiar gymnosperm – a pine tree.


needle-like leaves

cone containingseeds for reproduction

root system underground

stems

A pine tree A pine cone


Did you notice the leaves? They are like needles. As well, the other

most obvious feature is the cones.

Can you identify the leaves and cones in the photograph below?

A pine branch


14 Living things

Angiosperms (flowering plants)

The last plant group we'll look at is the one that you are probably most

familiar with – angiosperms, or flowering plants. What is the most

obvious feature of a flowering plant? The flowers, of course!

But, there are some flowering plants that don’t have obvious flowers.

See if you can pick the angiosperms (flowering plants).

yes no

• Is wheat a flowering plant?

• Is a tomato a flowering plant?

• Is a coconut palm a flowering plant?

• Is grass a flowering plant?

• Is a gum tree a flowering plant?

• Is a peach tree a flowering plant?

• Is an apple tree a flowering plant?

• Is a lettuce plant a flowering plant?

• Is barley a flowering plant?

• Is a banana palm a flowering plant?

They are all angiosperms, or flowering plants! It may have been harder

than you thought to identify flowering plants. It would have been easier

for you if you knew that flowering plants produce fruits and seeds. So if

the flowers weren’t obvious, then the fruits or the seeds may have been.

The drawings below show you some of the different types of fruit

produced by flowering plants.


blackberry plum pea acorn

Fruits of some angiosperms


The following drawings show you some of the different types of seeds

produced by flowering plants.

dandelion sycamore broad bean

Seeds of some angiosperms


Angiosperms can look very different from each other because there are

many shapes and arrangements of leaves and stems. Even the roots on

angiosperms can have different forms and patterns. But angiosperms

have one main similarity.

In Greek, angio- means container and sperm means seed. Use this

information to carry out the activity below.

Activity: Angiosperms

What do you think angiosperm means?

___________________________________________________________

___________________________________________________________

An angiosperm is a plant with its seeds inside a container, or fruit.

16 Living things

Plant groupsYou have read a lot of information about the different plant groups.

Now it’s time to summarise what you have learned so far.

Activity: What have you learned about plant groups?

Complete the following using information from this lesson.

Plant group Features Examples

algae • no roots, stems and leaves Hormosira

• live in _______________ _______________

bryophytes • have leaves but ________ roots

or ________. _______________

• ___________ plants

• live in __________ places

• reproduce by ___________

pteridophytes • have leaves _______________

• underground _______________ _______________

• reproduce by _______________

gymnosperms • roots, stems and leaves _______________

• produce seeds in _______________

_______________ _______________


angiosperm • have ______________ _______________

_______________ and _______________

_______________ _______________

• Flowers produce _______________

______________ that are

protected inside _____________


You can now use this information to carry out the exercise below.

Go to the exercises section and complete Exercise: – Plant groups.

What's next?Have you enjoyed learning about plants and using keys? Would you like

to try to draw your own key? Remember, a key uses the structural

features of living things to enable you to classify them into smaller and

smaller groups.

Here's an activity you can try. You might even like to do it as your

student research project.

Activity: A plant search

Go on an excursion to a garden or native bush area.

Observe at least five different plants than construct a key that could be

used to identify them.

18 Living things

You should show your key to someone else to try in your garden or bush

area. How successful were they? Do you need to change your key?

Write a few sentences to describe how the key was used.

You might like to include drawings or pressed, dried plant cuttings with

your key and report for your teacher.

If you are overseas, then do notsend plants to Australia. They may

have diseases that plants inAustralia do not have.

What did you achieve?Tick what you can do.

use a key to classify plants into the main plant groups

compare photographs with drawings of plants

complete a table summarising the features of the five main plant

groups.


Suggested answers

Check your responses against these suggested answers.

A quick look at each plant group

1 bryophyte

2 angiosperm

3 pteridophyte

4 algae

5 gymnosperm

Note: alga is one plant; algae is more than one plant of that kind.

Liverworts

1 No, liverworts don’t have roots

2 No, liverworts don’t have flowers.

3 Liverworts are called bryophytes because they are similar to mosses. They

do not have stems or roots but they do have simple leaves.

20 Living things

What have you learned about plant groups?

Plant group Features Examples

algae • no roots, stems and leaves

• live in water

Hormosira (Neptune’s

necklace), corallina, ulva

(sea lettuce)

bryophytes • have leaves but no roots or stems

• small plants

• live in moist places

• reproduce by spores

moss, liverwort

pteridophytes • have leaves

• underground stems

• reproduce by spores

treefern, bracken,

fishbone fern, maidenhair

fern

gymnosperms • roots, stems and leaves

• produce seeds in cones

cycad, fir tree, pine tree,

cypress, spruce, ginkgo,

redwood

angiosperm • have roots, stems and leaves

• flowers produce seeds which are

protected inside fruit.

wheat, tomato, coconut

palm, grass, gum tree,

peach tree, apple tree,

lettuce, barley, banana

palm, blackberry, plum,

pea, dandelion,

oak (makes acorns),

sycamore, broadbean


Exercise

Living things Name ___________________________

Teacher ___________________________

Exercise: Plant groups

Are there roots and stems?

Are there seeds?

Are there flowers?bryophytes

angiosperms

plants

no yes

no yes

no yes

pteridophytes

gymnosperms

Are there leaves?

algae

no yes

1 Use the key to identify the group to which each of the plants below

belongs. Write the group on the line beside the photograph.

a

callistemon (bottlebrush)

© State of New South Wales, Department of Education

and Training, 2004

22 Living things

b

pine tree

c

fern

© State of New South Wales, Department of Education

and Training, 2004.

2 Did you find it difficult to classify any of the plants in Question 1?

a Which one(s)?

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________


b Why? (What extra information did you need to make

a decision?)

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

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