Some vendors offer several different kinds of one essential oil.
These oils are listed as chemotypes. The energies and effects of light, soil, temperature, moisture and climate influence the life processes of plants and the formation of essential oils. Differences in plants arise as a result of isolation, mutation and evolution in the face of continued climatic change or stress. This process can eventually lead to the development of new species, but subtle yet permanent changes may arise even when the various plant forms remain botanically identical. When conditions cause the plants to permanently produce variations in the chemical makeup of their essential oils, these plants are known as chemotypes.