Which bryophyte was used as a surgical dressing during World war I?

Options

A. Sargassum
B. Funaria
C. Sphagnum
D. Porella

Answer

**Step-by-Step Solution:**

1. **Identify the Bryophyte in Question**: The question asks which bryophyte was used as a surgical dressing during World War I. We need to recall the bryophytes and their uses during that time.

2. **Recall Historical Context**: During World War I, there was a significant need for materials that could be used for medical purposes, specifically for treating wounds.

3. **Recognize the Role of Sphagnum**: Among bryophytes, sphagnum moss is well-known for its properties that make it suitable for use as a surgical dressing. It was widely used during WWI.

4. **Understand the Properties of Sphagnum**: Sphagnum moss creates a sterile environment around wounds. It helps in keeping the pH level low, which inhibits bacterial growth, making it effective for wound care.

5. **Evaluate Other Options**: The question may provide multiple-choice answers. We need to evaluate the other options to confirm that sphagnum is the correct answer:
- **Sargassum**: Not a bryophyte and primarily known for marine habitats.
- **Funeria**: Another bryophyte but used as a soil conditioner, not for surgical purposes.
- **Borrelia**: A genus of bacteria, not a bryophyte.

6. **Conclude the Answer**: Based on the above evaluations, we conclude that the bryophyte used as a surgical dressing during World War I is **Sphagnum**.

**Final Answer**: Sphagnum moss was used as a surgical dressing during World War I.

---