Carl Linnaeus was a brilliant botanist. He and his students explored many countries and discovered thousands of new types of plants. However, he is most famous for finding a way of organising these discoveries and naming them; a system that every biologist still uses today.

Complicated flowers

Download a pdf of the instructions here.

You will need...

A flower (preferably still growing) - anything from a garden weed to tree blossom will do!
A pencil
Paper

How long will it take?

You may like to spread this over two lessons.  In the first lesson you can get the students to draw and categorise their plants, in the second you can have a class discussion.  Alternatively the students can draw their plants at home and you will need only one lesson for the discussion.

What to do...

Students can work on their own or in small groups if they are more likely to contribute this way.  They can provide their own plants or you can supply each group with one - if you use plants from the table below you can see which ones are most closely related to each other, choose two or three from each group.

1.  Draw a picture of your flower.  In Linnaeus' time there was no photography and part of a botanist's job was to draw very accurate pictures of the plants they were studying.  Don't forget to include the leaves; you may even want to carefully look at the shape and type of roots.

You may want to guide the students by posing some questions like...

How tall is the flower?
What colour it is?
Does it have a smell?
What shape are the leaves?
How many petals are on each flower?

Not all the questions you ask need to be helpful in the classification.  Classification is made ever easier if you have yes or no answers.

2.  Write out the key features of your plant.  Look at the overall shape and height before looking at it in more detail.

3.  As a class have a look at the different features you have picked out as being important.  First make a list of all the key characteristics or questions they asked themselves.  Make a note of how many times the same question came up.  For example, every group  might ask 'What colour is the flower?' but only a few may ask 'How many stamen does the flower have?'.

4.  Ask the class to select the most important questions.    Is the shape of the leaves more important than the colour of the flower?  Choose a few of the most important questions to help you classify the class's plants.

5.  Using these questions try to group together the plants with similar characteristics.  It doesn't really matter if they have grouped all the white flowers together or all the plants of the same height, as long as they are putting them in some kind of order!

6.  They may want to do this by someone saying, 'My plant's flower have 6 petals and the leaves are dark green and shiny', and see if anyone else matches those characteristics.  The class can mingle, joining together into groups with people with similar plants.

7.  Were they right?  You can use the chart below to help you decide which plants are most closely related.


The following plant classification chart for some common types of flowering plant in the UK has many omissions.  Yet it illustrates some of the ways plants can be classified into the larger groups (the columns do not follow class, order or family).

Plants

Don't produce seeds

(mosses, algae, ferns)

 

 

 

 

Plants that produce seeds

plants that don't flower

(conifers)

 

 

 

 

Plants that flower

Leaves with branched veins

Flowers with 4 or 5 petals (or multiples of 4 or 5)

There are usually a large number of stamens.  Can clearly tell which are petals and which are sepals

(rosids)

Raspberries, strawberries, apples, apricots, roses

 

 

 

 

Plants produce long pods containing seeds

(rosids / fabaceae)

Peas and beans

 

 

 

 

Each flower head is often made up lots of much smaller flowers

(asterids / asterales)

Sunflowers, daisies, dandelions

 

 

 

Leaves with parallel veins and 3 or 6 petalled flowers (or multiples of 3)

(monocots)

 

Orchids, lilies, daffodils, tulip, grass, bamboo, pineapple, reeds and rushes

 

 

 

Branched veins on leaves but flowers with a multiple of three petals.

(magnoliids)

 

Magnolia, laurel

Many plants are now categorised genetically, not necessarily by how they look.  But the key characteristics to look for are the number of petals, how the petals are arranged in the flower, and the leaves.

A series of questions like these would be best for categorising these plants...

What is the vein structure on the leaf?
How many petals does the flower have?
How many stamens does the flower have?
Is the 'flower' a collection of many flowers?
What kind of seeds does the plant have?

Curriculum Links

Divided Up
Science

Working scientifically

Experimental skills and investigations

  • ask questions and devleop a line of enquiry based on observations of the real world, alongside prior knowledge and experience
  • make and record observations and measurements using a range of methods for different investigations

Analysis and evaluation

  • interpret observations and data, including identifying patterns and using observations, measurements and data to draw conclusions.
  • identify further questions arising from their results

Biology

Reproduction

  • Reproduction in plants, including flower structure, wind and insect pollination, fertilisation.


Scottish Curriculum Links

Science

 

SCN 2-01a

Planet Earth - Biodiversity and interdependence

I can identify and classify examples of living things, past and present, to help me appreciate their diversity. I can relate physical and behavioural characteristics to their survival or extinction. [Note: level 2]

 

SCN 3-01a

Planet Earth - Biodiversity and interdependence

I can sample and identify living things from different habitats to compare their biodiversity and can suggest reasons for their distribution.

 

SCN 4-01a

Planet Earth - Biodiversity and interdependence

I understand how animal and plant species depend on each other and how living things are adapted for survival. I can predict the impact of population growth and natural hazards on biodiversity.

linnaea borealisIf you enter the school office you may find lots of paper information on each student.  This is very likely to be ordered, perhaps by year group and then alphabetically.  Organising information like this makes it easier to find what we are looking for and also understand how it fits together.

Carl Linnaeus looked at nature in a similar way and spent his life putting it in order, at least on paper.

The image shows Linnaea borealis, a plant that was named after him.

To begin with he divided everything living into plants or animals; pretty obvious so far.  He then divided animals further into groups like mammals, reptiles or birds, and he divided plants into smaller groups as well.  He continued dividing the groups again and again, the members of each smaller group having something in common, until there was only one type of living thing in a group; this was a single species.

Working out how to group similar plants or animals together is not simple.  First Linnaeus had to decide what the most important characteristics were.  For animals, this could mean having feathers or scales.  In plants, he was famous for dividing them by the number of stamen or stigma the flowers had.

Key fact: Dividing plants and animals up into groups makes it easier to understand which species are most closely related - it also allows biologists to look at differences between animals of the same species.

 

 

Complicated flowers

Download a pdf of the instructions here.

You will need...

A flower (preferably still growing) - anything from a garden weed to tree blossom will do!
A pencil
Paper

What to do...

You will find out just how hard it is to pick the important features for classifying plants.

1.  Draw a picture of your flower.  In Linnaeus' time there was no photography and part of a botanist's job was to draw very accurate pictures of the plants they were studying.  Don't forget to include the leaves; you may even want to carefully look at the shape and type of roots.

2.  Write out the key features of your plant.  Look at the overall shape and height before looking at it in more detail.  You can do this by asking yourself a question and then answering it... 'What shape are the leaves?' - 'They have five small leaves attached to a single point'.  Take a look at this picture of a flower to help you decide which the important parts to look at are.

parts of flower_550

Here are a few questions you may want to ask...

How tall is the flower?
What colour it is?
Does it have a smell?
What shape are the leaves?
Are there veins visible on the leaves and what shape are they?
How many petals are on each flower?

3.  As a class, have a look at the different features you have picked out as being important.