Select the mismatched pair

Options

A. collateral and open vascular bundles- sunflower stem
B. Bicollateral vascular bundles-Maize stem
C. Concentric vascular bundles -ferns
D. Radial vascualr bundles -maize root

Explanation

To solve the question of selecting the mismatched pair from the given options regarding vascular bundles in plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Vascular Bundles**:
- Vascular bundles can be classified into different types: collateral, bicollateral, concentric, and radial. Each type has specific characteristics and examples.

2. **Analyze Each Option**:
- **Option 1**: Collateral and open vascular bundles in sunflower stem.
- In collateral vascular bundles, xylem is located on the inner side and phloem on the outer side. This is true for sunflower, which is a dicot.
- **Conclusion**: This option is matched correctly.

- **Option 2**: Bicollateral vascular bundles in maize stem.
- Bicollateral vascular bundles have one patch of xylem and two patches of cambium. They are typically found in plants from the Cucurbitaceae and Solanaceae families, not in maize, which belongs to the Gramineae family.
- **Conclusion**: This option is mismatched.

- **Option 3**: Concentric vascular bundles in ferns.
- In concentric vascular bundles, either xylem or phloem surrounds the other. This is characteristic of ferns.
- **Conclusion**: This option is matched correctly.

- **Option 4**: Radial vascular bundles in maize root.
- Radial vascular bundles have xylem and phloem arranged in alternating radii. This is true for the roots of both dicots and monocots, including maize.
- **Conclusion**: This option is matched correctly.

3. **Identify the Mismatched Pair**:
- After analyzing all options, the only mismatched pair is **Option 2**: Bicollateral vascular bundles in maize stem.

### Final Answer:
The mismatched pair is **bicollateral vascular bundles in maize stem**.

---