Reticulate venation is a characteristic of dicots. An exception to this generalisation is

Options

A. Calophyllum
B. Ficus
C. Hibiscus
D. Zizyphus.

Explanation

To solve the question regarding the exception to the generalization that reticulate venation is a characteristic of dicots, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- Reticulate venation refers to a network-like pattern of veins in leaves, typically found in dicotyledonous plants (dicots).
- Parallel venation is a characteristic of monocotyledonous plants (monocots), where veins run parallel to each other.

2. **Identify the Generalization**:
- The generalization states that reticulate venation is a characteristic feature of dicots.

3. **Look for Exceptions**:
- While most dicots exhibit reticulate venation, there are exceptions where some dicots may show parallel venation or where some monocots may exhibit reticulate venation.

4. **Evaluate the Given Options**:
- The options provided are:
- a) Calophyllum
- b) Ficus
- c) Hibiscus
- d) Ziziphus

5. **Analyze Each Option**:
- **Calophyllum**: This plant is known to exhibit reticulate venation, making it an exception.
- **Ficus**: This plant typically shows reticulate venation, so it does not qualify as an exception.
- **Hibiscus**: This plant also exhibits reticulate venation, thus not an exception.
- **Ziziphus**: This plant is known for reticulate venation as well, so it is not an exception.

6. **Conclusion**:
- The only option that serves as an exception to the generalization that reticulate venation is characteristic of dicots is **Calophyllum**.

### Final Answer:
The exception to the generalization that reticulate venation is characteristic of dicots is **Calophyllum**.

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