Despite the fact all living things have had a common origin, plants have diversified to such an extent they hardly show any relationship to the specimens of the other kingdoms.  Let us examine the unique characteristics of this kingdom.that

 Fig.2  Parts of a flowering dicotyledonous plant.

 Only the standard parts, are shown . 

Flowers, thorns tendrils etc, are not included here as they are modifications of these parts . .

Parts of a normal plant.

1. Roots.

These are the parts that grow towards the earth (geotropic) unlike the shoots They also have a tendency to grow towards water. (hydrotropic)

As they do not have nodes and internodes leaves and buds are absent. 

Normal roots arise from the base of the stem but in certain species, roots arise from the shoots which are called adventitious roots.

When you uproot a plant, root hairs break off. Root hairs have only one cell.

Roots perform the following functions;

i.  Absorb water and nutrients from the soil.  
ii.  Holding the plant firmly to the soil against the forces of wind and water.
iii. Storing of food (starch) . Large reservoirs of food are known as yams.
iv. A few plants produce buds that grow into new plants. These are called adventitious buds.

2.Stem.

Fig.3  Sugar cane stem filled with sugary sap
The stem has nodes from which the leaves and buds arise.  These may be much branched as in most dicots.  or single as in palms. They generally grow towards light (phototropic) and  upwards.Some stems may remain underground and grow sideways. as in ginger. In that case only the leaves come above the soil.

Do you know? What of the plant is a potato tuber?  A fruit, root or a stem?

Functions;

i. To spread the foliage and the flowers, in a way to get the maximum amount of light.

ii. Climbers, creepers and runners produce adventitious roots, tendrils or thorns  to hold on to a support.  

iii. Some stems store sugar or starch.
iv. Conducting water and nutrients from root to shoot. (xylem tubes)
v. Conducting food from leaves to roots.(Ohloem tubes)

3. Leaf

leaves are the food factories of the plants. 

They take in carbon dioxide from the air and combine with water to make sugar. This is the process known as photosynthesis. As the energy is obtained from sunlight the leaves are generally flat to capture the light.  They are also very thin exposing many stomata to the atmosphere for the exchange of gases.(Stomata are the opening on the leaf surface)

Fig.4  The trifoliate leaves of a leguminous plant. 

Functions of a leaf.

i.    Leaves manufacture food by photosynthesis.

ii. They exchange gases through stomata , the opening mostly found on the under surface of the leaf.

iii. They store water. which is used for photosynthesis and for cooling, when exposed to  direct sunlight.

iv.  In some plants they get modified into tendrils, or thorns.

v. In a few rare cases such as bryophillum and begonia the leaf margin can produce young plants.

                                            KINGDOM OF PLANTAE

Vascular Plants.

1. Ferns

    Reproduces by spores found on the under surface of leaves.

    Young leaves emerge rolled up from the bud.

eg. Bracken fern. Maiden hair fern (Adiantum). Tree fern.           

There are two main groups of tree ferns in New Zealand: Cyathea and Dicksonia.  They are easily distinguished since Cyathea is scaly and Dicksonia is hairy.

2. Gymnosperms