Question

How do you identify the midrib of a leaf having parallel venation?

Answer 1

Hint: Leaf veins are present on either parallel or reticulate (net-like). Venation in addition to providing the water & energy to the plants and the leaves; it also provides mechanical as well as the biochemical support. Thus variations in the leaf venation also have the wide range of applications. Further research on this can help us to know much better about them.

Complete answer:
Each leaf normally has a leaf blade which is known as the lamina, which is also called the widest part of the leaf. Some leaves are generally attached to the plant stem by the petiole. Leaves which do not have the petiole & are directly attached to the plant stem are normally called the sessile leaves. Leaves also have the stipules, which are small green appendages usually found at the base of petiole. Most leaves do have a midrib, which moves along the length of the leaf and branches to the each side in order to produce the veins of a vascular tissue. The edge of the leaf is generally called the margin.
If the leaf is Cut in half, across the leaf & look for organisation

By making the cross section of the leaf:
Netted venation is normally going to look like chaos because the veins which are going out & branching. This is generally like the maple leaf venation. Picture cutting a maple leaf in half & looking at the cut.
Parallel is going to have a quite large dot in the center if there is the large central vein & smaller dots on the either side, which is relatively in a row. This, because the venation is parallel & if you cut the parallel lines you will get a paralleled dots.

Note: When veins (or the nerves) are generally arranged parallel to each other all over the leaf blade or the lamina, then it is called as parallel venation. Bananas, bamboo, wheat, grasses & the maize are generally few examples of the parallel venation.