Stem distinctly differentiated in to node and internode in :-

Options

A. Psilopsida
B. Lycopsida
C. Sphenopsida
D. Pteropsida

Answer

To solve the question "Stem distinctly differentiated into node and internode in:", we will analyze the provided options and determine which group of plants exhibits this characteristic.

### Step-by-Step Solution:

1. **Understanding the Question**:
- We need to identify which plant group has stems that are clearly divided into nodes and internodes. Nodes are points on the stem where leaves or branches arise, while internodes are the segments of the stem between the nodes.

2. **Analyzing the Options**:
- **Coelopsida**: This group does not have stems that are distinctly differentiated into nodes and internodes.
- **Lycopsida**: Similar to Coelopsida, Lycopsida does not exhibit this characteristic in their stem structure.
- **Sphenopsida**: This group includes plants like Equisetum (horsetails), which are known for having stems that are clearly differentiated into nodes and internodes. The upright aerial stems of Equisetum show a distinct pattern of nodes and internodes.
- **Pteropsida**: This group does not typically have stems that are distinctly differentiated into nodes and internodes.

3. **Identifying the Correct Answer**:
- Based on the analysis, the only group that exhibits the characteristic of having a stem distinctly differentiated into nodes and internodes is **Sphenopsida**.

4. **Conclusion**:
- Therefore, the correct answer to the question is **C. Sphenopsida**.