The phenomenon of floral parts acting as a barrier to self pollination is

Options

A. Heterostyly
B. Dichogamy
C. Dicliny
D. Herkogamy.

Answer

To solve the question regarding the phenomenon of floral parts acting as a barrier to self-pollination, we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for a phenomenon where floral parts act as a barrier to self-pollination. This means we need to identify a mechanism that prevents pollen from fertilizing the ovule of the same flower.

2. **Evaluate the Options**:
- **Option 1: Heterostyle**: This phenomenon involves flowers having stamens and pistils of different lengths. While it does prevent self-pollination by having different types of flowers, it does not involve a physical barrier created by the floral parts themselves. Therefore, this option is incorrect.

- **Option 2: Dichogamy**: In dichogamy, the maturation of stamens and pistils occurs at different times, which prevents self-pollination. However, there is no physical barrier involved in this process. Thus, this option is also incorrect.

- **Option 3: Declinae**: This term refers to the presence of unisexual flowers on a plant, which also prevents self-pollination. However, similar to the previous options, it does not involve floral parts acting as a physical barrier. Hence, this option is incorrect as well.

- **Option 4: Hercogamy**: Hercogamy is the phenomenon where floral parts act as physical barriers to self-pollination. This often involves structures that cover the stigma, preventing pollen from the same flower from fertilizing its ovules. This is the correct answer as it directly addresses the question.

3. **Conclusion**: After evaluating all the options, the correct answer to the question is **Option 4: Hercogamy**.

### Final Answer:
The phenomenon of floral parts acting as a barrier to self-pollination is **Hercogamy**.