Question

Explain the various types of venation.

Answer 1

VARIOUS TYPES OF VENATION

The arrangement and distribution of veins and veinlets on the lamina of a leaf is called venation.

They are of three types:

1. Reticulate Venation:

When the veins are irregularly distributed to form a channel, it is known as Reticulate Venation.

It is the characteristic feature seen in dicots.

They are of two types:

1. Unicostate or Pinnate Reticulate:
   Leaf having a single main mid-rib.
   Example: Hibiscus, Mango
2. Multicostate or Palmate Reticulate:
   Having two or more mid-ribs arising from a single point.
   They are further divided as:
   1. Multicostate convergent:
      Many mid-ribs in a curved fashion from base of blade to its apex.
      Example: Zizyphus (Beri)
   2. Multicostate divergent:
      Many mid-ribs arise at the base of the leaf and then diverge from one another towards the margin.
      Example: Papaya, Cucurbita

2.  Parallel Venation:

Veins are parallel and do not form a network.

They are of two types:

1. Unicostate or Pinnate parallel:
   Lamina has a single prominent midrib from which lateral veins arise which run towards the margin.
   Example: Canna, Banana
2. Multicostate or Palmate parallel:
   Several leaves run parallel to each other.
   They are further divided as:
   1. Multicostate convergent:
      Principal veins appear from the base of the lamina and converge at the apex.
      Example: Bamboo
   2. Multicostate divergent:
      Main veins appear from the base of the lamina and converge at the apex.
      Example: Fan palm

3. Furcate Venation:

Dichotomously branched veins. Also known as forked venation.
Example: Nephrolepis (Fern)

Comments

Thanks A Lot But,You should also attach diagram