(introduction...)

Pick up some leaves of a mango tree or coffee tree. Let us look at them.

· Leaves are usually of a green colour, more or less dark.
· They are joined to the stem by a stalk called the leaf- stalk.
· The leaf-stalk is continued into the leaf by the midrib.
· Other smaller veins branch out from the midrib. These are the primary and secondary veins.
· The whole flat part of the leaf is called the leaf blade or lamina.

A leaf

The leaf-stalk

Some plants have a short leaf- stalk.
For example, coffee, orange, hibiscus, guava.

Some plants have a long leaf- stalk.
For example, papaw or papaya, sweet potato

The leaf-stalk

Some plants do not have a leaf- stalk.
The leaves of maize, millet or rice surround the stem.
There is no leaf- stalk.

The veins

In the middle of the leaf there is the midrib.
On each side of the midrib other veins branch off.
These are the primary veins.
They are smaller. These primary veins divide into many still smaller veins.

Perhaps you have seen a leaf that has been eaten by insects.
The leaf tissue has gone and only the veins are left. It is like a spider's web.

What are the veins for?

They carry the sap.
The sap passes along the stem vessels.
Then it enters the vein vessels.

Cut a palm frond and you will see the sap flow. The vessels of the palm frond carry the sap.

In a man's body, the vessels carry the blood.
In a plant, the vessels carry the sap.

Sap is the blood of plants.