Stem in ferns is underground, monopodial root stock and called

Options

A. rhizome
B. corm
C. bulb
D. sucker

Answer

### Step-by-Step Solution:

1. **Understanding the Structure of Ferns**:
- Ferns are vascular plants that reproduce via spores and have a unique structure. They typically have a stem that can be found above or below ground.

2. **Identifying the Type of Stem**:
- In ferns, the stem is often found underground. This underground stem is known for its ability to grow horizontally.

3. **Defining Monopodial Growth**:
- Monopodial growth refers to a type of growth where there is a single main stem that grows continuously, producing side branches. In ferns, this characteristic is present in their underground stems.

4. **Recognizing the Correct Term**:
- The specific term used for the underground monopodial rootstock in ferns is "rhizome." Rhizomes are specialized stems that grow horizontally beneath the soil surface.

5. **Eliminating Other Options**:
- The other options provided (comb, bulb, sucker) do not accurately describe the underground stem of ferns.
- A bulb is a storage organ found in some plants.
- A sucker refers to a shoot that arises from the base of a plant or from its roots.
- A comb does not relate to plant structures.

6. **Conclusion**:
- Therefore, the correct answer to the question is "rhizome," as it accurately describes the underground monopodial rootstock of ferns.

### Final Answer:
The stem in ferns is underground, monopodial rootstock and is called **rhizome**.