Question

Multicostate parallel venation occurs in
A) Banana and Canna
B) Mango and Peepal
C) Grasses and Palms
D) Castor and Tapioca
E) Castor and China rose

Answer 1

Hint: The meaning of Costa is the principal vein or the mid rib. And, multicostate parallel venation refers to the presence of more than one principal vein. The plants having parallel venation are monocots.

Complete Answer:
The organisation of veins and veinlets in the leaf blade is called venation. There are two principal types of venation – Reticulate venation & Parallel venation. In reticulate venation, veins and veinlets unite to form a reticulum or a network. In parallel venation, veins and veinlets are arranged parallel to each other.

Reticulate venation is of two types –
(1) Reticulate unicostate or pinnate type in which the leaf blade has only one principal vein or midrib that gives off many lateral veins that proceed toward the margin and apex of the lamina and form a network. Examples are – Mango, Guava and Peepal etc.
(2) Reticulate multicostate or palmate type –
This is again of two types –
(a) Reticulate multicostate convergent type – In this type, many principal veins arise from the tip of the petiole. At the base of the lamina they are arranged closely. They diverge from one another in the middle of the lamina and converge towards the apex of leaf, e.g. Camphor, Zizyphus, Tejpat, China rose, plum etc.
(b) Reticulate multicostate divergent type – In this type, many principal veins arise from the tip of the petiole and then diverge towards the margin of leaf blade, e.g. Cotton, Castor, Tapioca, Cucurbita, Grapes etc.

Parallel venation is of two types –
(1) Parallel unicostate or pinnate type in which the leaf blade has only one principal vein (mid rib) that gives off many lateral veins. The lateral veins are not divided into veinlets and they run parallel towards the margin of the leaf blade. Examples of this type are – Banana, Ginger, Canna.
(2) Parallel multicostate or palmate type in which the leaf blade has many principal veins.

This is again divided of two types –
(a) Parallel multicostate convergent type – In this type, many principal veins arise from the tip of petiole that run in a curved manner in lamina and converge towards the apex of leaf blades. Examples of this type are – Wheat, Sugar-cane, and grasses etc.
(b) Parallel multicostate divergent type – In this type, many principal veins arise from the tip of petiole and diverge towards the margin of leaf. The veins are not divided into veinlets. Examples of this type are – Toddy palm and Fan palm.
Mango, Peepal, China rose, Castor and Tapioca are examples of reticulate venation. Banana and Canna are examples of unicostate parallel venation. Grasses and palms are examples of multicostate parallel venation.

Thus, the correct answer is C, i.e., Grasses and Palms.

Note: Parallel venation is a characteristic feature of monocotyledons, and reticulate venation is a distinguishing feature of dicotyledons.