| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Vitis vinifera | Fruit | -- | -- | Jim Duke's personal files. | |
| Prunella vulgaris | Plant | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Linum usitatissimum | Seed | -- | 55.0 | * | |
| Centaurea cyanus | Flower | -- | -- | Jim Duke's personal files. |