Ferns are characterised by

Options

A. cambium
B. xylem vessles
C. young leaves with circinate ptyxis and presence of ramenta
D. all of the above.

Answer

To answer the question "Ferns are characterised by," we can break down the characteristics of ferns step by step:

### Step 1: Understanding Ferns
Ferns are a group of vascular plants that reproduce via spores and do not produce seeds or flowers. They belong to the division Pteridophyta.

### Step 2: Key Characteristics of Ferns
1. **Young Leaves**: Ferns are known for their young leaves, which are often coiled and referred to as "fiddleheads" before they unfurl.
2. **Sarsenae**: This term likely refers to the arrangement of leaves or leaflets in ferns. In some contexts, it may refer to specific structures or arrangements that help in photosynthesis or reproduction.
3. **Ramenta**: Ferns possess hair or scale-like structures called ramenta, which protect the young leaves from mechanical injuries and environmental factors.
4. **Vascular Tissue**: Ferns have well-developed vascular tissues, including xylem and phloem, but they do not have xylem vessels in the same way that flowering plants do.

### Step 3: Analyzing the Options
- **Cambium**: This is a layer of tissue in plants that produces new cells and is not a characteristic of ferns.
- **Xylem Vessels**: Ferns do not have true xylem vessels; they have tracheids instead.
- **Young Leaves with Sarsenae**: This is a characteristic of ferns.
- **Ramenta**: The presence of ramenta is indeed a characteristic of ferns.
- **All of the Above**: Since some options are incorrect, this cannot be the answer.

### Conclusion
Based on the analysis, ferns are characterized by young leaves with sarsenae and the presence of ramenta. Therefore, the correct answer is that ferns are characterized by young leaves with sarsenae and the presence of ramenta.

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