In which one of the following pollination is autogamous?

Options

A. Geitonogamy
B. Xenogamy
C. Chasmogamy
D. Cleistogamy

Explanation

To determine which type of pollination is autogamous, we need to understand the concept of autogamous pollination and the types of pollination mentioned in the question.

### Step-by-Step Solution:

1. **Define Autogamous Pollination**:
- Autogamous pollination refers to self-pollination, where pollen from the anther of a flower fertilizes the ovule of the same flower.

2. **Identify Requirements for Autogamous Pollination**:
- For a flower to be autogamous, it must be a bisexual flower, meaning it contains both male (anthers) and female (pistil) reproductive structures.

3. **Differentiate Types of Pollination**:
- **Geitonogamy**: Transfer of pollen between different flowers of the same plant. Although it involves different flowers, it is still considered self-pollination genetically.
- **Xenogamy**: Transfer of pollen between flowers of different plants, which is a form of cross-pollination.
- **Cosmogamy**: Involves open flowers where anthers are exposed, allowing for pollen to be carried by wind or insects, which is not self-pollination.
- **Clistogamy**: Refers to flowers that are completely closed, where the anthers do not expose themselves, allowing for pollen transfer within the same flower, thus leading to self-pollination.

4. **Conclusion**:
- Among the options provided, **Clistogamy** is the type of pollination that is autogamous, as it allows for self-pollination within the same flower.

### Final Answer:
**Clistogamy** is the type of pollination that is autogamous.

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