A concentric amphivasal (leptocentric) vascular bundle is one in which

Options

A. Centrally located phloem is surrounded by the xylem of xylem surround phloem
B. Centrally located xylem is surrounded by phloem
C. Xylem is flanked by phloem on the interior and exterior side only
D. phloem is flanked by the xylem on interior side only

Answer

To solve the question regarding the configuration of a concentric amphivasal (leptocentric) vascular bundle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Vascular Bundle**: A strand of vascular tissue in plants, consisting of xylem and phloem.
- **Concentric**: Refers to the arrangement where one type of tissue surrounds another.
- **Amphivasal (Leptocentric)**: Specifically refers to a type of vascular bundle where phloem is surrounded by xylem.

2. **Identify the Configuration**:
- In a concentric amphivasal vascular bundle, the arrangement is such that the phloem is located in the center and is surrounded by xylem.
- This is the opposite of amphicribral (heterocentric), where xylem is in the center and surrounded by phloem.

3. **Examples**:
- An example of a plant with amphivasal vascular bundles is the **eucalyptus** (Eucalyptus spp.), where the phloem is surrounded by xylem.

4. **Conclusion**:
- Therefore, a concentric amphivasal (leptocentric) vascular bundle is characterized by having phloem centrally located and surrounded by xylem.

### Final Answer:
A concentric amphivasal (leptocentric) vascular bundle is one in which the centrally located phloem is surrounded by xylem.

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