Question

Unicostate venation is called as
(a) Palmate
(b) Pinnate
(c) Reticulate
(d) Parallel

Answer 1

The veins arise from the midvein (midrib) present in the center of the leaf lamina from base to the apex. These veins grow perpendicular to the midvein towards the margin of the leaf and are parallel to one another.

Complete Step by Step answer:
Venation is the arrangement of veins on the leaves. It is basically of 2 types, reticulate and parallel. Reticulate venation involves the irregular distribution of veins to form a network. Parallel venation is the venation in which the veins run parallel to each other. Pinnate venation is also known as unicostate venation. In this type, the lamina has a single principal vein or midrib. It produces lateral veins. Palmate venation is also called a multicostate venation. In this, lamina has more than one principal vein.
So, the correct answer is, ‘(b) Pinnate.’

Additional Information:
From the presence of mid- veins, parallel venation can be differentiated into two types:
1. Pinnate parallel venation: In this, the veins arise from the midvein (midrib) present in the center of the leaf lamina from base to the apex. These veins grow perpendicular to the midvein towards the margin of the leaf and are parallel to one another. This venation is also called Unicostate parallel venation.
2. Palmate parallel venation: In this case, there are many prominent veins that are parallel to one another. This venation is also known as Multicostate parallel venation. It is also of two types, Convergent and Divergent parallel venation.
- In the case of reticulate venation, the veins are present in an irregular manner forming a network. Examples of plants, which exhibit reticulate venation, include rose, tulsi, hibiscus, papaya, ficus.
- The Leaves of monocot plants show parallel venation and the leaves of dicot plants show reticulate venation.
- Veins are the part of the vascular tissue, arising from the stem to the leaf of the plant. Veins are made up of xylem and phloem, and enclosed in the parenchyma, sclerenchyma and bounded by the sheath cells.
- Venation also provides mechanical support, protection, coordination in the development of the plants.

Note: The venation architecture is enormously distributed among the diverse species of plants. Based on venation a plant can be differentiated into different groups it has its importance in the recognition and in differentiating the plants in their characteristics. Variation in leaf venation is mostly exhibited by the angiosperms.