Superficial outgrowth of stem or leaves which do not possess vascular cylinder and becomes thick due to deposition of silica or calcium carbonate is

Options

A. Prickles
B. Spines
C. Bristles
D. thorns

Explanation

To solve the question regarding the superficial outgrowth of stem or leaves that do not possess a vascular cylinder and become thick due to the deposition of silica or calcium carbonate, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a specific type of outgrowth from stems or leaves that lacks a vascular cylinder and becomes thick due to mineral deposits (silica or calcium carbonate).

2. **Identifying Key Terms**:
- Superficial outgrowth
- No vascular cylinder
- Thickened by silica or calcium carbonate

3. **Analyzing the Options**: The options provided are Prickles, Spines, Bristles, and Thorns. We need to determine which of these fits the description given in the question.

4. **Defining Each Option**:
- **Prickles**: These are superficial outgrowths of stems or leaves that do not have vascular bundles. They can be easily removed and are often thickened due to silica or calcium carbonate.
- **Spines**: These are modified leaves or parts of leaves that have vascular tissue. They are not the correct answer since they possess vascular bundles.
- **Bristles**: These are stiff hairs that can harden due to silica deposition but do not fit the description of being a superficial outgrowth of stems or leaves.
- **Thorns**: These are modified stems with vascular tissue, so they do not fit the criteria either.

5. **Conclusion**: Based on the definitions, the correct answer is **Prickles**. They are superficial outgrowths that do not possess vascular bundles and can become thick due to the deposition of silica or calcium carbonate.

### Final Answer:
The superficial outgrowth of stem or leaves which do not possess a vascular cylinder and becomes thick due to the deposition of silica or calcium carbonate is **Prickles**.