Flowering plants have developed certain outbredding devices to discourage self-pollination and encourage cross-pollination. One of these is not an examples of such outbreeding device.

Options

A. Dicliny
B. Dichongamy
C. Herkogamy
D. Cleistogamy

Explanation

To solve the question regarding the outbreeding devices in flowering plants, we need to analyze the options provided and determine which one does not encourage cross-pollination. Here’s a step-by-step breakdown:

### Step 1: Understand the Concept of Outbreeding Devices
Outbreeding devices in flowering plants are mechanisms that discourage self-pollination and promote cross-pollination. This is important for genetic diversity and the overall health of plant populations.

### Step 2: Analyze the Options
We have four options to consider:

1. **Unisexuality**: This refers to plants that have male and female flowers on separate individuals. This arrangement promotes cross-pollination because it requires pollen to be transferred from one plant to another.

2. **Dichogamy**: This is the phenomenon where the male and female reproductive organs mature at different times. This timing difference prevents self-pollination and encourages cross-pollination as it requires pollen from another plant.

3. **Hercogamy**: This involves physical barriers between the anther (where pollen is produced) and the stigma (where pollen lands). These barriers also promote cross-pollination by preventing self-pollination.

4. **Clistogamy**: This is a condition where flowers are closed and self-pollination occurs. Since the flowers do not open, pollen does not have the opportunity to be transferred to other plants, thus promoting self-pollination instead of cross-pollination.

### Step 3: Identify the Correct Answer
From the analysis above, the option that does not promote cross-pollination is **Clistogamy**. This is because it leads to self-pollination due to the closed nature of the flowers.

### Conclusion
The correct answer to the question is **Clistogamy**.

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