The heterosporous pteridophytes are

Options

A. Lycopodium and Pteris
B. Selaginella and Psilotum
C. Selaginella and Salvinia
D. Dryopteris and Adiantum.

Explanation

### Step-by-Step Solution:

1. **Understanding Heterospory**:
- The term "heterosporous" refers to the production of two different types of spores: microspores (male) and megaspores (female).
- Microspores are typically smaller and develop into male gametophytes, while megaspores are larger and develop into female gametophytes.

2. **Significance of Heterospory**:
- Heterospory is significant in the evolutionary context as it has led to the development of seeds in vascular plants. This adaptation is crucial for plant reproduction and survival.

3. **Identifying Heterosporous Pteridophytes**:
- Some pteridophytes exhibit heterospory. The question asks for examples of such plants.
- Notable examples of heterosporous pteridophytes include **Sileginella** and **Salvinia**.

4. **Evaluating Options**:
- Option 1: Lycopodium and Terris - Incorrect, as Lycopodium is not heterosporous.
- Option 2: Sileginella and Silotum - Partially correct, as Sileginella is heterosporous, but Silotum is not.
- Option 3: Sileginella and Salvinia - Correct, as both are heterosporous.
- Option 4: Dryopteris and Endiantum - Incorrect, as neither is heterosporous.

5. **Conclusion**:
- The correct answer is **Sileginella and Salvinia**, as both are examples of heterosporous pteridophytes.