What ar the small brown or yellow spots on the underside or margin of fern sporophylls ?

Explanation

To answer the question about the small brown or yellow spots on the underside or margin of fern sporophylls, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structures**: The small brown or yellow spots observed on the underside or margin of fern sporophylls are known as "sori."

2. **Understand the Nature of Sori**: Sori are clusters that appear as yellowish or brown spots. They are not just random spots; they serve a specific function in the life cycle of ferns.

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