| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Mentha pulegium | Plant | 10.0 | 20.0 | Duke, J. A. Writeups or information summaries on approximately 2,000 economic plants, USDA, ARS, Beltsville, MD 20705. | |
| Mentha pulegium | Essential Oil | -- | 1000.0 | * | |
| Origanum majorana | Plant | -- | -- | ANON. 1948-1976. The Wealth of India raw materials. Publications and Information Directorate, CSIR, New Delhi. 11 volumes. | |
| Angelica archangelica | Root Essent. Oil | -- | -- | * | |
| Pinus sylvestris | Root | -- | -- | Guenther, E., The Essential Oils, 6 volumes, D. van Nostrand, New York, 1948-1952. |