| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Aesculus hippocastanum | Leaf | -- | -- | Jim Duke's personal files. | |
| Zea mays | Leaf | -- | -- | * | |
| Medicago sativa | Leaf | -- | -- | * | |
| Crataegus monogyna | Leaf | -- | -- | * | |
| Taraxacum officinale | Leaf | -- | -- | * | |
| Vaccinium myrtillus | Leaf | -- | -- | * | |
| Urtica dioica | Leaf | -- | -- | Jim Duke's personal files. |