When phloem is present on both sides of the xylem, the vasecular bundle is said to be

Options

A. collateral
B. bicollateral
C. radial
D. conjoint

Answer

### Step-by-Step Solution:

1. **Understanding Vascular Bundles**: Vascular bundles are the structures that contain the xylem and phloem, which are responsible for the transport of water, nutrients, and food in plants.

2. **Types of Vascular Bundles**: There are different types of vascular bundles based on the arrangement of xylem and phloem. The main types include:
- **Simple Vascular Bundles**: These have xylem and phloem arranged alternately.
- **Concentric Vascular Bundles**: In these bundles, one type of vascular tissue surrounds the other.

3. **Collateral Vascular Bundles**: In collateral vascular bundles, xylem and phloem are arranged side by side on the same radius. This means that the phloem is located on one side of the xylem.

4. **Bicollateral Vascular Bundles**: When phloem is present on both sides of the xylem, the vascular bundle is classified as bicollateral. This arrangement allows for more efficient transport of nutrients and is found in certain plant families.

5. **Examples of Bicollateral Vascular Bundles**: Bicollateral vascular bundles are commonly found in plants belonging to the families Cucurbitaceae (like cucumbers), Solanaceae (like tomatoes), and Convolvulaceae (like morning glories).

### Final Answer:
When phloem is present on both sides of the xylem, the vascular bundle is said to be **bicollateral**.

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