Which one of the following is a xerophytic plant in which the stem is modified into the flat green and succulent structure
Or
Phylloclade is found in

Options

A. Opuntia
B. Casuarina
C. Hydrilla
D. Acacia

Answer

To solve the question, "Which one of the following is a xerophytic plant in which the stem is modified into the flat green and succulent structure? Or Phylloclade is found in," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Xerophytic Plants**: These are plants adapted to survive in environments with little water, typically found in dry areas like deserts.
- **Phylloclade**: This is a modified stem that is flattened and green, capable of photosynthesis, and is succulent (stores water).

2. **Analyze the Options**:
- **Opuntia**: Known as prickly pear, it has stems that are modified into flat, green, succulent structures, which can perform photosynthesis.
- **Casuarina**: This plant has modified stems called cladodes, which are not flat but are also adaptations to dry conditions.
- **Hydrilla**: An aquatic plant, not xerophytic, so it cannot be the answer.
- **Acacia**: In Acacia, the petiole (leaf stalk) is modified, not the stem.

3. **Identify the Correct Answer**:
- Among the options, **Opuntia** is the only plant where the stem is modified into a flat green and succulent structure, which fits the definition of a phylloclade.

4. **Conclusion**:
- Therefore, the correct answer is **Opuntia**.