What is true about cork cambium?

Options

A. It is extrastelar cambium in dicot stem
B. In dicot roots it arises from the cells of cortex region
C. It is also known as phellogen
D. Both ( a ) & ( c )

Answer

### Step-by-Step Solution:

1. **Definition of Cork Cambium**: Cork cambium, also known as phellogen, is a type of lateral meristematic tissue found in plants. It is responsible for the production of cork cells, which form the outer protective layer of the bark.

2. **Location**: Cork cambium is located between the cork (phellem) and the phloem in the stems and roots of dicotyledonous plants. It acts as a boundary layer that separates these two tissues.

3. **Extracellular Cambium in Dicot Stem**: The statement that cork cambium is an extracellular cambium in dicot stems is true. This means it is located outside the vascular tissue (xylem and phloem) and contributes to the secondary growth of the plant.

4. **Cork Cambium in Dicot Roots**: The statement that cork cambium arises from the cells of the cortex in dicot roots is incorrect. In dicot roots, cork cambium does not arise from the cortex; instead, it typically arises from the pericycle or the outer layer of the vascular cylinder.

5. **Alternate Name**: Cork cambium is also known as phellogen or phallosan. This is a correct statement as it refers to the same tissue.

6. **Conclusion**: Based on the analysis of the statements regarding cork cambium, the true statements are:
- Cork cambium is an extracellular cambium in dicot stems.
- Cork cambium is also known as phallosan.

### Final Answer:
The true statements about cork cambium are:
- It is an extracellular cambium in dicot stems.
- It is also known as phallosan.