| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Betula sp. | Plant | -- | -- | Jeffery B. Harborne and H. Baxter, eds. 1983. Phytochemical Dictionary. A Handbook of Bioactive Compounds from Plants. Taylor & Frost, London. 791 pp. | |
| Daucus carota | Fruit | -- | -- | * | |
| Eriodictyon californicum | Plant | -- | -- | Leung, A. Y. and Foster, S. 1995. Encyclopedia of Common Natural Ingredients 2nd Ed. John Wiley & Sons, New York. 649 pp. | |
| Eriodictyon californicum | Shoot | -- | 22.5 | * | |
| Eucalyptus globulus | Resin, Exudate, Sap | -- | -- | * | |
| Eucalyptus citriodora | Resin, Exudate, Sap | -- | -- | * | |
| Juglans nigra | Fruit | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Ribes nigrum | Leaf | -- | -- | * |