In distichous condition

Options

A. First leaf stands over the second
B. Second leaf stands over the first
C. Third leaf stands over the first
D. Fourth leaf stands over the first.

Answer

### Step-by-Step Solution:

1. **Understanding Phyllotaxis**:
- Phyllotaxis refers to the arrangement of leaves on a stem. It is important to understand this concept as it forms the basis for answering the question.

2. **Types of Phyllotaxis**:
- There are three main types of phyllotaxis:
- Opposite
- Spiral
- Whorled

3. **Focus on Distichous Condition**:
- The question specifically asks about the distichous condition, which is a type of spiral phyllotaxis. In this condition, leaves are arranged in two vertical rows on opposite sides of the stem.

4. **Understanding Leaf Arrangement in Distichous Condition**:
- In distichous phyllotaxis (also known as 1/2 phyllotaxy), the arrangement of leaves occurs such that:
- The first leaf is positioned at a certain point on the stem.
- The second leaf is positioned directly opposite the first leaf.
- The third leaf will be positioned above the first leaf.
- The fourth leaf will be positioned above the second leaf.

5. **Identifying the Correct Option**:
- Given the options:
- Option 1: First leaf stands over the second.
- Option 2: Second leaf stands over the first.
- Option 3: Third leaf stands over the first.
- Option 4: Fourth leaf stands over the first.
- The correct option is Option 3, which states that the third leaf stands over the first leaf.

6. **Conclusion**:
- Therefore, in a distichous condition, the arrangement of leaves is such that the third leaf is positioned directly above the first leaf.