Chili de Arbol (aka 's beak chile and rat's tail chile)
The Chile de árbol (Spanish for tree chili) is a small and potent Mexican chili pepper also known as bird's beak chile and rat's tail chile. These chilis are about 5 to 7.5 cm (2.0 to 3.0 in) long, and 0.65 to 1 cm (0.26 to 0.39 in) in diameter. Their heat index is between 15,000 - 30,000 Scoville units. The peppers start out green and turn a bright red color as they mature. Chile de árbol peppers can be found fresh, dried, or powdered. As dried chiles, they are often used to decorate wreaths because they do not lose their red color after dehydration.
Outdoor grown Chile de árbol peppers Since they are largely for decorative and garnishing purposes, they are readily substituted in cooking. The Chile de árbol pepper can be traded with Cayenne pepper (30,000–50,000 Scoville units) or Pequin pepper (30,000–60,000 Scoville units). The inside of the fruit where the seeds are attached can be removed from the pepper to tone down its heat; seeds themselves contain no heat.