Structure of the Leaf
A leaf is a thin, flat, green and broad outgrowth of a stem. Let’s go in the detail of the common structure present in all the leaves –
· Node –The point from where a leaf arises on the stem is called the node. Node also allows other branches to develop on the stem.
· Lamina (leaf blade) – The thin, flat and expanded part of the leaf which is clearly visible to our eyes whenever we see a leaf. Remember, this is the whole green part of the leaf.
· Leaf Margin – The edge of the lamina is called the margin of the leaf or leaf margin.
· Leaf Apex – A little pointed tip of the leaf is called the leaf apex.
· Petiole (Leaf Stalk) – The small cylindrical shaped stick in the bottom of the lamina and above the node is the petiole. Basically, it joins the lamina to the stem. Few leaves do not have a petiole and directly grow from the node. They are called sessile or epetiolate leaves.
· Midrib –You guys must have observed a thick line passing through the lamina of the leaves. This is the midrib. The midrib extends from the petiole till the leaf apex (tip).
· Veins and Veinlets – You all must have observed that the midrib takes out many zigzag type of lines called the veins. The veins further take out some thinner lines called the veinlets. The petiole, midrib, veins and veinlets together help to transport water from the stems to the leaves and the food prepared by the leaves to the complete plant.
· Leaf Base – The petiole has a slightly swollen part at it end called the leaf base.