Normally in dicot stems, phellogen develops from

Options

A. Hypodermis
B. Phellem
C. Endodermal cells
D. Epidermal & pericycle cells

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks from which tissue the phellogen (also known as cork cambium) develops in dicot stems during secondary growth.

2. **Identifying the Options:**
The given options are:
- A) Hypodermis
- B) Phloem
- C) Endodermal cells
- D) Epidermal and pericycle cells

3. **Analyzing Each Option:**
- **Option D (Epidermal and pericycle cells):** These are the outermost layers of the stem. During secondary growth, they get ruptured due to the expansion of the stem, so they cannot be the source of phellogen.
- **Option C (Endodermal cells):** These cells are located beneath the epidermis and are involved in the transport of water and nutrients. They do not give rise to phellogen, as phellogen develops before the endodermis is involved in secondary growth.
- **Option B (Phloem):** Phloem is responsible for the transport of nutrients. Phellogen does not develop from phloem; rather, it is produced by phellogen itself.
- **Option A (Hypodermis):** The hypodermis consists of several layers beneath the epidermis. During secondary growth, the cells in the hypodermis can resume meristematic activity and differentiate into phellogen, making this the correct answer.

4. **Conclusion:**
The correct answer is **A) Hypodermis**, as it is the tissue from which phellogen develops in dicot stems during secondary growth.

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