What is incorrect for pollination by water?

Options

A. Emergent flowers above the level of water are pollinated by insects or winds
B. Pollination can take place inside or on water surface
C. All aquatic plants are pollinated by water
D. Pollen grains often posses mucilagenous sheath

Answer

To determine the incorrect statement regarding pollination by water (hydrophily), we will analyze each of the provided statements step by step.

### Step-by-Step Solution:

1. **Understanding Hydrophily**:
- Hydrophily is a type of pollination where water serves as the medium for transferring pollen grains from the male part of a flower (anther) to the female part (stigma).

2. **Evaluating Statement 1**:
- **Statement**: "Emergent flowers above the level of water are pollinated by insects and winds."
- **Analysis**: This statement is correct. Flowers that are above the water surface are typically pollinated by insects and wind, not by water.

3. **Evaluating Statement 2**:
- **Statement**: "Pollination can take place inside or on the water surface."
- **Analysis**: This statement is also correct. Pollination can occur for flowers submerged in water or those that are floating on the water surface.

4. **Evaluating Statement 3**:
- **Statement**: "All aquatic plants are pollinated by water."
- **Analysis**: This statement is incorrect. Not all aquatic plants rely on water for pollination; some may be pollinated by other means such as wind or insects.

5. **Evaluating Statement 4**:
- **Statement**: "Pollen grains often possess a mucilaginous sheath."
- **Analysis**: This statement is correct. Many water-pollinated plants have a mucilaginous sheath around their pollen grains, which helps protect them from wetting and aids in their buoyancy.

### Conclusion:
The incorrect statement regarding pollination by water is **Statement 3**: "All aquatic plants are pollinated by water."

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