A monocot leaf has parallel venation but there are some monocot leaves which have reticulate venation viz.

Options

A. Calophyllum
B. Corymbium
C. Dioscorea (Yams)
D. All the above

Answer

### Step-by-Step Solution:

1. **Understanding Leaf Venation**:
- Monocot leaves typically exhibit parallel venation, where the veins run parallel to each other along the length of the leaf.
- Dicot leaves, on the other hand, generally show reticulate (or net-like) venation, where the veins form a complex network.

2. **Identifying the Exception**:
- While most monocots have parallel venation, there are exceptions where some monocot leaves display reticulate venation.

3. **Examples of Monocots with Reticulate Venation**:
- One such example of a monocot that exhibits reticulate venation is **Dioscorea**, commonly known as yams.
- This is significant because it deviates from the typical characteristics of monocot leaves.

4. **Conclusion**:
- Therefore, the correct answer to the question about monocot leaves that have reticulate venation is **Dioscorea (yams)**.