What does a herbarium contain ?

Explanation

### Step-by-Step Solution:

1. **Definition of Herbarium**: A herbarium is a collection of preserved plant or fungal specimens. It serves as a repository for various species of plants and fungi.

2. **Historical Context**: Many herbaria were established in the year 1600, indicating the long-standing tradition of collecting and preserving plant specimens for scientific study.

3. **Herbarium Sheets**: The specimens are typically mounted on herbarium sheets. These sheets are specifically designed to hold and display the collected plant material.

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