Environmental heterophylly is observed in :

Options

A. Cotton
B. Coriander
C. Larkspur
D. Buttercup

Answer

To solve the question regarding environmental heterophylly, we need to understand the concept of heterophylly and how it applies to different plants.

### Step-by-Step Solution:

1. **Understanding Heterophylly**:
- Heterophylly refers to the phenomenon where a single plant exhibits different types of leaves at different stages of development or in response to environmental conditions.

2. **Types of Heterophylly**:
- There are two main types of heterophylly:
- **Developmental Heterophylly**: Different leaf forms appear due to the growth stages of the plant.
- **Environmental Heterophylly**: Different leaf forms appear in response to varying environmental conditions.

3. **Analyzing the Options**:
- **A. Cotton**: Exhibits developmental heterophylly. The juvenile leaves are different from mature leaves but do not change based on the environment.
- **B. Coriander**: Similar to cotton, it shows developmental changes but not environmental heterophylly.
- **C. Larkspur**: Primarily shows developmental heterophylly.
- **D. Buttercup**: Exhibits environmental heterophylly. The leaves change form depending on whether the plant is in a terrestrial habitat or an aquatic habitat.

4. **Conclusion**:
- Based on the definitions and analysis of the options, the correct answer is **D. Buttercup**, as it demonstrates environmental heterophylly by having different leaf structures based on its habitat.

### Final Answer:
**Environmental heterophylly is observed in: D. Buttercup.**