In plants, a sorus is a cluster of spore-producing structures on the underside of a fern frond.
Sori are an important part of a fern's reproductive system.
Examples:
The sorus on the fern leaf contains many spores.
We can see the sorus on the underside of the fern leaf.
The sorus helps the fern make new plants.
The sorus is like a little spore family under the leaf.
The sorus is where the fern keeps its baby plants.
The sorus is like a secret garden for the fern.