| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Piper nigrum | Fruit | -- | -- | * | |
| Ribes nigrum | Leaf | -- | -- | * | |
| Althaea officinalis | Leaf | -- | -- | * | |
| Althaea officinalis | Flower | -- | -- | * | |
| Aesculus hippocastanum | Leaf | -- | -- | Jim Duke's personal files. | |
| Teucrium chamaedrys | Plant | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Solidago virgaurea | Flower | -- | -- | * | |
| Solidago gigantea | Leaf | -- | -- | * | |
| Salix alba | Leaf | -- | -- | * | |
| Hypericum perforatum | Flower | -- | -- | * | |
| Morus alba | Leaf | -- | -- | * | |
| Tilia sp. | Flower | -- | -- | * |