Lateral meristem is

Options

A. Procambium and phelloderm
B. Interfascicular and phelloderm
C. Phellogen and phelloderm
D. Phellogen and fascicular cambium

Answer

### Step-by-Step Solution:

1. **Definition of Lateral Meristem**: Lateral meristem is a type of secondary meristem that is responsible for the lateral growth (increase in girth) of plants. It is derived from the primary meristem through a process called re-differentiation.

2. **Formation of Lateral Meristem**: The lateral meristem arises when primary meristematic tissues divide and then undergo re-differentiation. This process allows the plant to develop additional tissues that contribute to its width.

3. **Function of Lateral Meristem**: The primary function of lateral meristem is to facilitate lateral growth in plants. This growth is essential for the plant to increase its girth or diameter, which is important for structural support and nutrient transport.

4. **Components of Lateral Meristem**: Lateral meristem consists of several components, including:
- **Intrafascicular Cambium**: This cambium is located between the vascular bundles and is responsible for the formation of secondary xylem and phloem.
- **Cork Cambium (Phellogen)**: This is formed from the outer cortex and contributes to the formation of the protective outer layer of the plant.

5. **Distinction from Other Meristems**: Unlike primary meristems that are involved in the elongation of the plant (apical growth), lateral meristems are specifically involved in increasing the girth of the plant.

6. **Analysis of Options**: In the context of the question, we analyze the options provided:
- **Option A**: Pro cambium and phallodum - Incorrect, as phallodum (secondary cortex) is not part of lateral meristem.
- **Option B**: Intrafascicular cambium and phallodum - Incorrect, as phallodum is not part of lateral meristem.
- **Option C**: Phallogen and phallodum - Incorrect, as phallodum is not part of lateral meristem.
- **Option D**: Phallogen and fascicular cambium - Correct, as phallogen refers to cork cambium which is part of lateral meristem.

7. **Conclusion**: The correct answer is that lateral meristem consists of intrafascicular cambium and cork cambium (phallogen), which are essential for the lateral growth of the plant.