Select a correct statement w.r.t. extrastelar secondary growth

Options

A. Phellogen is purely secondary in origin
B. Phelloderm is also called cork
C. Periderm includes all nonsuberised layers formed by phellogen activity
D. Phellem includes loosely arranged parenchyma

Answer

To solve the question regarding the correct statement with respect to extrastelar secondary growth, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Extrastelar Secondary Growth**:
- Extrastelar secondary growth refers to the growth that occurs outside the vascular bundles in plants, primarily involving the cork cambium (also known as felogen).

2. **Identify the Role of Cork Cambium**:
- Cork cambium is a type of lateral meristem that produces secondary tissues. It is responsible for the formation of cork (felum) and secondary cortex (feloderm).

3. **Differentiate Between Cork, Cork Cambium, and Secondary Cortex**:
- Cork (felum) is the outer protective layer formed from the outer cells of the cork cambium.
- Secondary cortex (feloderm) is formed from the inner cells of the cork cambium.

4. **Define Periderm**:
- The periderm is a protective tissue that includes the cork (felum), the cork cambium (felogen), and the secondary cortex (feloderm).

5. **Evaluate the Given Statements**:
- **Statement 1**: "Felogen is purely secondary in origin."
- This statement is true because cork cambium (felogen) is a secondary tissue.
- **Statement 2**: "Feloderm is also called cork."
- This statement is false because feloderm refers to the secondary cortex, not cork.
- **Statement 3**: "Periderm includes all non-subarised layers formed by phallogen activity."
- This statement is false as periderm includes subarised layers (cork) formed by cork cambium activity.
- **Statement 4**: "Phallum includes loosely arranged parenchyma."
- This statement is false because phallum (cork) is composed of cells that are subarised and not loosely arranged parenchyma.

6. **Select the Correct Statement**:
- The correct statement regarding extrastelar secondary growth is: "Felogen is purely secondary in origin."