Which of the following does not show protogyny?

Options

A. Polyalthia
B. Aristolochia
C. Rose
D. Sunflower

Answer

To determine which of the following does not show protogyny among the options provided (Polyalthia, Aristolochia, Rose, and Sunflower), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Protogyny**:
- Protogyny is a reproductive strategy in flowering plants where the female reproductive organs (gynosium) mature before the male reproductive organs (androsium). This helps in promoting cross-fertilization by reducing the chances of self-fertilization.

2. **Analyze Each Option**:
- **Polyalthia**: This plant exhibits protogyny, where the female parts mature before the male parts.
- **Aristolochia**: This plant also shows protogyny, with the gynosium maturing prior to the androsium.
- **Rose**: Roses are known to be protogynous as well, with the female reproductive structures maturing before the male structures.
- **Sunflower**: In contrast, sunflowers are protandrous, meaning that the male parts mature before the female parts.

3. **Identify the Correct Answer**:
- Since we are looking for the option that does not show protogyny, we find that the sunflower (Helianthus) is the only one among the options that is protandrous.

### Conclusion:
The answer to the question "Which of the following does not show protogyny?" is **Sunflower**.

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