However, terpenes are plentiful throughout nature. More than 20,000 of the special odiferous molecules are found in thousands of species of plants other than cannabis. Delta 3 carene, specifically, is also produced by basil, bell pepper, cedar, pine, and rosemary, among other plants.
Limonene is a terpene that conveys a smell of citrus (orange, tangerine, lemon, lime, or grapefruit), juniper, rosemary, or peppermint. Lemons and other citrus fruits contain large quantities of limonene, especially in the rind. Thus, when one perceives an aroma of citrus in cannabis (or any other plant), it is literally the same chemical that produces this odor in fruits such as lemons, limes, and oranges.