Compact orange pepper plants in the genus Capsicum.

There are several completely different plants referred to by the name of pepper; all are used in food for the "hot" sensation that particular chemical components induce on the tongue.

1. Various plants in the family Piperaceae, notably the genus Piper, including the black pepper that appears on virtually every dining room table in parts of the world. Different preparations of the same Piper nigrum plant also produce "white" and "green" peppercorns. Also, the genus Peperomia, which is included in the Peperomiaceae family by some authors.
2. Plants in the genus Capsicum in the family Solanaceae, including bell peppers and chile peppers. These plants have given rise to the Scoville scale to measure the "hotness" of a pepper.
3. Pink peppercorns, also called "Peruvian pepper" or "Caribbean pepper," are from a plant related to Cashews; species Schinus molle, in the family Anacardiaceae.
4. Szechuan peppercorns are produced by a plant of the family Rutaceae, species Zanthoxylum piperitum.

Wikibooks Cookbook has more about this subject:

Pepper

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