The term polyderm is applied to the

Options

A. wound cork
B. inner cork
C. cork around the knots
D. composite periderm

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "Polyderm":**
- The term "polyderm" is derived from two components: "poly" meaning many or more than two, and "derm" which refers to a layer. Therefore, polyderm refers to a structure that consists of multiple layers.

2. **Identifying Relevant Layers:**
- In plant anatomy, the term polyderm is often associated with the periderm, which is a protective tissue that replaces the epidermis in plants during secondary growth. The periderm is composed of three distinct layers:
- **Phellogen (cork cambium):** This is the meristematic layer that produces new cells.
- **Phellem (cork):** This is the outer layer that provides protection.
- **Phelloderm:** This is the inner layer that can also contribute to the protective function.

3. **Distinguishing Between Single and Multiple Layers:**
- It is important to note that not all cork or protective layers qualify as polyderm. For example, wound cork and cork around knots are typically single-layer structures and do not constitute a polyderm.

4. **Conclusion:**
- Given that polyderm refers to a structure with multiple layers, the correct application of the term is to the composite periderm, which consists of the three layers mentioned above (phellogen, phellem, and phelloderm). Therefore, the answer is that the term polyderm is applied to composite periderm.

**Final Answer:**
The term polyderm is applied to composite periderm, which consists of multiple layers (phellogen, phellem, and phelloderm).

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