Name the ring of hygroscopic tooth-like structures encircling the mouth of the capsule of mosses.

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure**: The question asks about a specific structure found in mosses, particularly in the capsule that contains spores.

2. **Identifying the Capsule**: Mosses produce a capsule that is involved in the dispersal of spores. This capsule has an apical portion that plays a role in regulating the discharge of spores.

3. **Maturation of the Capsule**: As the capsule matures, it develops into two main parts: the operculum and the peristome. The operculum is the lid that covers the capsule.

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