In earlier systems of classification basis of classification of plants were all of the following except:

Options

A. Root modifications
B. Leaf venation
C. Natural affinities
D. Number of cotyledons

Answer

To solve the question regarding the bases of classification of plants in earlier systems, we need to analyze the options provided and determine which one does not serve as a basis for classification.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the basis of classification of plants in earlier systems, specifically identifying which option does not belong to these bases.

2. **Identify the Options**: The options provided typically include:
- Root modification
- Leaf venation
- Number of cotyledons
- Natural affinities

3. **Evaluate Each Option**:
- **Root Modification**: This is a valid basis for classification. Plants can be classified based on whether they have tap roots, fibrous roots, or adventitious roots.
- **Leaf Venation**: This is also a valid basis. Leaf venation can be classified as parallel or reticulate, which helps in distinguishing plant groups.
- **Number of Cotyledons**: This is a well-known classification method. Plants can be classified into monocots (one cotyledon) and dicots (two cotyledons).
- **Natural Affinities**: This term refers to the inherent relationships and attractions between organisms and their environments. It is not a concrete basis for classification in the earlier systems, as it is more abstract and does not provide a clear method for categorizing plants.

4. **Conclusion**: The option that does not serve as a basis for classification in earlier systems is **Natural Affinities**.

5. **Final Answer**: Therefore, the correct answer is **Option 3: Natural Affinities**.