Which of the following aestivation involves non-uniform overlapping of petals?

Options

A. Valvate
B. Twisted
C. Imbricate
D. Contorted

Answer

To solve the question regarding which type of aestivation involves non-uniform overlapping of petals, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Aestivation**: Aestivation refers to the arrangement of petals or sepals in a flower bud before it opens. It is important to know the different types of aestivation to answer the question correctly.

2. **Identify the Types of Aestivation**: The options provided are velvet, twisted, imbricate, and contorted. We need to analyze each type to see which one has non-uniform overlapping of petals.

3. **Analyze Velvet Aestivation**: In velvet aestivation, the petals lie next to each other without any overlapping. Therefore, this type does not involve overlapping at all.

4. **Analyze Twisted Aestivation**: In twisted aestivation, the petals overlap each other uniformly. One side of each petal is inside while the other side is outside, leading to uniform overlapping. Thus, this type does not meet the criteria of non-uniform overlapping.

5. **Analyze Imbricate Aestivation**: In imbricate aestivation, the petals do overlap, but the overlapping is non-uniform. Some petals may be completely inside while others are completely outside, leading to a non-uniform arrangement. This matches the requirement of the question.

6. **Analyze Contorted Aestivation**: Contorted aestivation is essentially the same as twisted aestivation, where the petals overlap uniformly. Therefore, this option is also incorrect.

7. **Conclusion**: After analyzing all the options, we find that the type of aestivation that involves non-uniform overlapping of petals is **Imbricate**.

### Final Answer:
The correct answer is **Imbricate**.