Question

Whorled, simple leaves with reticulate venation are present in which of the following plants?
A. Calotropis
B. Azadirachta
C. Hibiscus
D. Alstonia

Answer 1

Hint: Venation is the arrangement of veins in leaves. Monocots have parallel venation whereas dicots have reticulate venation. Similarly, the arrangement of leaves on a plant is called phyllotaxy. It is either alternate, spiral, opposite, or whorled.

Complete answer:
Leaves are the pivotal photosynthetic organs in most plants along with green stems. These leaves exhibit different kinds of venation. It is the arrangement of veins in a leaf. Venation is of two types:
> Reticulate venation- It is the irregular arrangement of veins in leaves. It is mostly displayed by dicots.
> Parallel venation- in this type veins run parallel to each other. It is mostly displayed by monocots.
The arrangement of leaves on a plant is called phyllotaxy. It is of three types:
> Alternate- in this type, a single leaf arises from each node in an alternate manner. Example: sunflower.
> Opposite- in this type, a pair of leaves arise at each node and lie opposite to each other. Example: guava.
> Whorled- more than two leaves arise at each node and form a whorl. Example: alstonia.
On the basis of difference in shape and arrangement in leaves, they are categorized into two categories:
> Simple leaves- in simple leaves, the leaf is joint to a stem via petiole. Example: hibiscus, alstonia.
> Compound leaves: these leaves exhibit proper differentiation of leaf blade into leaflets. Example: rose, neem. Compound leaves are further divided into pinnately compound in leaves and palmately compound leaves.

As per the discussion above, it is clear that from the given options the correct answer is option D - Alstonia.

Note:
The pinnately compound leaves are those which emerge from both sides of midrib. They are further divided into unipinnate, bipinnate and tripinnate. The palmately compound leaves are those which emerge only from one point such as in the palm. They are further classified into unifoliate, bifoliate, trifoliate, and quadrifoliate.