In which of the following plant flowers are invariably autogamous ?

Options

A. Commelina
B. Viola
C. Oxalis
D. None of the above

Answer

To determine which plant flowers are invariably autogamous, we need to understand the concepts of autogamy and the types of flowers present in different plants.

### Step-by-Step Solution:

1. **Understanding Autogamy**:
- Autogamy refers to the process of self-pollination, where pollen from the anther of a flower fertilizes the ovule in the same flower. For a flower to be invariably autogamous, it must always self-pollinate without exception.

**Hint**: Remember that autogamy is self-pollination, while cross-pollination involves pollen from a different flower.

2. **Types of Flowers**:
- There are two main types of flowers in angiosperms:
- **Chasmogamous Flowers**: These flowers have exposed stamens and stigmas, allowing for cross-pollination.
- **Clistogamous Flowers**: These flowers are closed, meaning their stamens and stigmas are not exposed. This structure facilitates self-pollination since no external pollen can enter.

**Hint**: Identify the characteristics of chasmogamous and clistogamous flowers to understand their pollination methods.

3. **Analyzing the Given Options**:
- The question provides options: Camelina, Viola, and Oxalis.
- All these plants are known to have both chasmogamous and clistogamous flowers. This means that while they can self-pollinate through their clistogamous flowers, they also have flowers that can engage in cross-pollination.

**Hint**: Check if the plants mentioned have both types of flowers, as this will affect their ability to be invariably autogamous.

4. **Conclusion**:
- Since Camelina, Viola, and Oxalis all possess both types of flowers, they cannot be classified as having flowers that are invariably autogamous. For a plant to be considered invariably autogamous, it must exclusively have clistogamous flowers.

**Final Answer**: None of the above options (Camelina, Viola, Oxalis) have flowers that are invariably autogamous.

### Summary:
- Autogamy is self-pollination.
- Chasmogamous flowers allow for cross-pollination, while clistogamous flowers are closed and promote self-pollination.
- The plants listed (Camelina, Viola, Oxalis) have both flower types, thus cannot be invariably autogamous.