| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Pyrus communis | Fruit | -- | 0.001 | -0.4 | * |
| Quercus phellos | Stem | 0.01 | 0.3 | -0.4 | * |
| Quercus stellata | Stem | -- | 0.04 | -0.4 | * |
| Quercus alba | Stem | -- | 0.04 | -0.4 | * |
| Quercus rubra | Seed | -- | 0.02 | -0.3 | * |
| Quercus alba | Bark | 0.3 | 1.5 | -0.4 | * |
| Raphanus sativus | Root | -- | -- | * | |
| Rheum rhabarbarum | Pt | -- | -- | * | |
| Rhodymenia palmata | Plant | -- | -- | * | |
| Rhus glabra | Stem | -- | 0.25 | -0.4 | * |
| Ribes rubrum | Fruit | -- | -- | * | |
| Ribes nigrum | Fruit | -- | 0.002 | -0.4 | * |
| Ribes uva-crispa | Fruit | -- | -- | * | |
| Rosa canina | Fruit | 0.4 | 2.1 | 0.1 | * |
| Rubus chamaemorus | Fruit | -- | -- | * | |
| Rubus idaeus | Leaf | 0.4 | 2.5 | -0.2 | * |
| Rumex crispus | Root | 0.6 | 2.5 | -0.2 | * |
| Ruscus aculeatus | Root | 0.4 | 1.4 | -0.3 | * |
| Salix alba | Bark | 0.2 | 1.1 | -0.5 | * |
| Salvia officinalis | Leaf | -- | -- | * |