Select the incorrect statement with respect to the prothallus of pteridophyta.

Options

A. It is gametophytic phase .
B. It is multicellular and free-living .
C. It is well differentiated with vascular tissue .
D. It is small and undifferentiated.

Answer

To solve the question regarding the incorrect statement about the prothallus of pteridophyta, we will analyze each statement provided in the options.

### Step-by-Step Solution:

1. **Understanding Pteridophyta**:
- Pteridophytes are known as the oldest vascular plants. They have specialized tissues (xylem and phloem) for the transport of water and nutrients.

2. **Identifying Prothallus**:
- The prothallus is the gametophyte stage of pteridophytes. It is crucial for reproduction as it produces gametes.

3. **Analyzing Each Statement**:
- **Statement 1**: "It is gametophytic phase."
- This statement is **correct**. The prothallus is indeed the gametophyte phase of pteridophytes.

- **Statement 2**: "It is multicellular and free living."
- This statement is also **correct**. The prothallus is multicellular and exists independently (free-living).

- **Statement 3**: "It is well differentiated with vascular tissue."
- This statement is **incorrect**. The prothallus does not have vascular tissues; it is not well differentiated like the sporophyte stage of pteridophytes. The mature sporophyte has vascular tissues, while the prothallus does not.

- **Statement 4**: "It is small and undifferentiated."
- This statement is **incorrect**. While the prothallus is small, it is not completely undifferentiated; it has some degree of differentiation, but it lacks vascular tissues.

4. **Conclusion**:
- The incorrect statement regarding the prothallus of pteridophyta is that it is "well differentiated with vascular tissue." Therefore, the correct answer to the question is that this statement is incorrect.

### Final Answer:
The incorrect statement with respect to the prothallus of pteridophyta is: **"It is well differentiated with vascular tissue."**

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