The index to the plant species found in a particular area is provide in:

Options

A. Flora
B. Monographs
C. Manuals
D. Catalogue

Answer

To solve the question regarding the index to the plant species found in a particular area, we will analyze the options provided and determine which one correctly represents the concept of plant species in a specific region.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the term that refers to the index of plant species found in a specific area. We need to identify the correct terminology that describes this concept.

2. **Analyzing the Options**:
- **Option A: Flora**: This term refers specifically to the plant species present in a particular area. It encompasses all the plant life in that region.
- **Option B: Monograph**: A monograph is a detailed written study of a single specialized subject, which may include various aspects of a taxonomic group but does not specifically refer to an index of species in a location.
- **Option C: Manuals**: Manuals are handbooks that provide information for identifying plants, but they do not serve as an index of species found in a particular area.
- **Option D: Catalog**: A catalog is a list of species names but does not specifically indicate the plant species found in a particular area.

3. **Identifying the Correct Answer**: Based on the definitions:
- The term that best fits the description of an index to the plant species found in a particular area is **flora**. This term specifically refers to the collection of plant species in a given region.

4. **Conclusion**: Therefore, the correct answer to the question is **flora**.

### Final Answer:
The index to the plant species found in a particular area is provided in: **flora**.