The flowers of all these plants show assured seed- set even in the absence of pollinators, except in

Options

A. Sunflower
B. Common pansy
C. Oxalis
D. Commelina

Answer

To solve the question "The flowers of all these plants show assured seed-set even in the absence of pollinators, except in," we need to analyze the options provided and understand the concepts of autogamy, clistogamy, and homogamy.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which plant's flowers do not guarantee seed set in the absence of pollinators. This implies that we are looking for a plant that relies on pollinators for seed production.

2. **Identify Key Terms**:
- **Autogamy**: Self-pollination where pollen from the anther of a flower fertilizes its own stigma.
- **Clistogamy**: A form of autogamy where flowers do not open, ensuring that self-pollination occurs without the need for pollinators.
- **Homogamy**: A condition where the anthers and stigma mature at the same time, allowing for self-pollination, but the flowers may still open.

3. **Evaluate the Options**:
- **Sunflower**: Sunflowers exhibit homogamy, meaning they can self-pollinate, but they do not guarantee seed set without pollinators.
- **Common Pansy**: Common pansy is known to have clistogamous flowers, which means they can set seeds without pollinators.
- **Other Options**: We would need to analyze other options similarly to determine if they exhibit clistogamy or autogamy.

4. **Conclusion**: Based on the definitions and characteristics:
- The sunflower is the only plant among the options that does not show assured seed set in the absence of pollinators, as it relies on homogamy rather than clistogamy.

5. **Final Answer**: The correct answer is **Sunflower**.