| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Arctium lappa | Seed | 11.7 | 30000.0 | Jim Duke's personal files. | |
| Forsythia suspensa | Fruit | -- | -- | * | |
| Cnicus benedictus | Seed | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Arctium lappa | Plant | -- | -- | * | |
| Arctium lappa | Fruit | -- | -- | Jim Duke's personal files. |