phellogen arises from

Options

A. an outer layer of cortex
B. Epidermis
C. phloem
D. all the above.

Answer

To answer the question "Phellogen arises from," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Phellogen**: Phellogen, also known as cork cambium, is a type of lateral meristem involved in secondary growth in plants. It is responsible for the production of cork (phellem) on the outer side and secondary cortex on the inner side.

2. **Identifying the Source**: The cork cambium (phellogen) arises from the outer layer of the cortex. This means that during the process of secondary growth, the cells in the outer cortex differentiate to form the cork cambium.

3. **Role of Cork Cambium**: Once formed, the cork cambium produces cork cells towards the outside and secondary cortex towards the inside. This process helps in protecting the plant and contributes to its overall growth.

4. **Eliminating Incorrect Options**: The question may provide multiple options. We need to identify that the epidermis and phloem are primary permanent tissues and do not contribute to the formation of cork cambium. Therefore, these options can be ruled out.

5. **Final Answer**: Based on the above reasoning, we conclude that phellogen arises from the outer layer of the cortex.

### Final Answer:
Phellogen arises from the outer layer of the cortex.