Vascular bundles of Cycas/Pinus stem are

Options

A. Conjoint, collateral and closed
B. Conjoint, collateral and open
C. Conjoint, bicollateral and open
D. Conjoint, bicollateral and closed.

Answer

To answer the question about the vascular bundles of Cycas and Pinus stems, we will analyze the characteristics of these vascular bundles step by step.

### Step-by-Step Solution:

1. **Identify the Type of Vascular Bundles**:
- The vascular bundles in Cycas and Pinus are classified as **conjoined**. This means that both xylem and phloem are present on the same radius within the vascular bundle.

2. **Determine the Arrangement of Vascular Bundles**:
- These vascular bundles are also **collateral**. In collateral vascular bundles, the phloem is located on the outer side and the xylem is on the inner side. This arrangement is typical for many plants, including Cycas and Pinus.

3. **Check for the Presence of Cambium**:
- The vascular bundles in Cycas and Pinus are described as **open**. This indicates that there is a layer of cambium present between the xylem and phloem. The cambium is responsible for secondary growth in plants.

4. **Review the Options**:
- Now, we can review the provided options:
- **Option A**: Conjoined, Collateral and Closed - Incorrect (because they are open)
- **Option B**: Conjoined, Collateral and Open - Correct
- **Option C**: Conjoined, Bicollateral and Open - Incorrect (they are not bicollateral)
- **Option D**: Conjoined, Bicollateral and Closed - Incorrect (they are not bicollateral and not closed)

5. **Conclusion**:
- The correct answer is **Option B: Conjoined, Collateral and Open**.