SUMMARY

Most plants have similar external features such as leaves, stems and flowers. Certainexternal features of these parts can be similar or different. Plants can be grouped according to the external features. Plants which are similar in a certain external feature can be put in the same group. Plants can be also be grouped according to their similarities in other external features such as thorns and leaves. 

Observing and Recognising External Features of Plants

FLOWERING PLANTS

            

NON-FLOWERING PLANTS

              

WOODY STEM

     

NON-WOODY STEM

               

TYPE OF LEAVES

         

     

                          

               

      

Part of Sunflower

Sunflowers – Planting to Harvest

Planting 

The seed is about half an inch long. It has a hard, striped covering. The covering 

protects the soft inside (the part that is tasty to eat). What the covering protects, 

and what you like to eat, is the food that the sunflower needs to begin to grow 

into a plant. Let’s plant the seed and watch it change and grow! 

In the spring, when the ground is warm, and the soil is soft, you can plant your 

seed. The seed needs to be buried in the soil where it can be warmed by the 

sun, watered by the rain, and fed by nutrients and oxygen trapped in the soil. 

Now underground, the hard covering of your seed splits open, and a little, white 

root appears! The root is the first part of the sunflower to grow. It will grow 

downward because of the force of gravity. The roots will hold the sunflower in the 

ground. This is a big job because your sunflower may grow to be over seven feet 

tall! The roots will also help feed the plant so that it can grow to be so tall.  

Growing 

I see it! Your sunflower has begun to grow! There is a small green shoot pushing 

up out of the soil. This is the beginning of the plant’s stem, and it grows up into 

the air (instead of down into the ground like the root) because it needs the sun’s 

light in order to do its job.

Leaves start to form in pairs on the stem as it grows taller. The leaves and the 

roots of your sunflower both feed it so it can become big and strong and then 

flower. The roots collect water and nutrients from the soil. The leaves catch 

energy from the sun. The energy helps the plant create food in a process called 

photosynthesis. This is a big word! It is bigger than I, Araña Pequeña! 

Because the leaves cannot produce food without energy from the sun, your 

sunflower leans towards the sunlight all day. As the sun moves from east to west 

across the sky, the plant will lean directly toward it. 

Now that the leaves are helping the roots feed your plant, it grows very fast. In 

two months, your sunflower may grow to be seven feet tall! How much do you 

grow in two months? In a year?  

Flowering 

Look! There is a bud forming at the top of the stem, above the highest pair of 

leaves. The bud is the protected, growing flower. There are strong, green, 

pointed petals covering it as it becomes bigger. 

When the bud begins to form, your sunflower won’t grow much taller. The bud is 

eating up the food that was used before to make leaves and a strong, tall stem. 

One morning, your sunflower bud begins to open. The strong, green petals open 

slowly. Watch the big yellow petals appear! These have been growing inside the 

bud. Inside the circle of bright yellow petals is a dark disk. This disk is made up of 

hundreds of tiny buds. These buds are smaller than I, Araña Pequeña! They 

won’t grow very big, but they give your sunflower a special name. Your sunflower 

is a composite flower – or a number of flowers that together form what looks 

like only one, large flower. Let’s take a closer look at this composite flower! 

Each tiny bud in the disk has its own reproductive parts. The female part is called 

the pistil. The pistil is made up of a stigma, a style and an ovary. The male part 

is called the stamen. The stamen is made up of a filament and an anther. 

Do you know how a sunflower reproduces? The process is called pollination. 

And sunflowers need insects to help them. Watch the bee that has landed on 

your sunflower! The bee is attracted by the bright yellow petals. When the bee 

lands on the sunflower, pollen from the stamen (the male part) of the flower gets 

stuck to the legs of the bee. When the bee flies away and lands on a different 

sunflower some of the pollen rubs off onto the pistil (the female part) of that 

flower. This is how plants are pollinated. 

Once one of the little flowers in the disk is pollinated, it can grow a seed.

Harvesting 

More and more seeds start to grow in the sunflower disk. The food from the

roots and from photosynthesis is now going into the growing seeds. Your 

sunflower may have more than 2000 seeds! 

By fall, all the seeds have grown to their full size, about half an inch long. Now 

farmers will harvest the seeds. Some of the seeds will be eaten by people like 

you and me. The ones that are not harvest might be eaten by small animals like 

squirrels and chipmunks. Do you know what else sunflower seeds are used for? 

Sunflower seeds can be pressed to make oil. The oil is used for cooking or in 

paint or soap. They are also used as birdseed, and to feed farm animals. And 

some of the seeds are saved to be planted. Without these seeds, we wouldn’t get 

any new sunflower plants next spring! 

External Features of Plants

Most plants have the same main part : leaves, stems, flowers and fruits. However these features do not look the same.

Most plants have green leaves. However, some have yellow or red leaves. Some leaves are shiny and some are dull. The surface of leaves are smooth or rough. The shape of leaves can be irregular, oval, round or long.

OBJECTIVE

You will learn :

• to observe and recognise external features of plants.
• that plants can be grouped according to external features.
• that plants can be grouped in many ways