| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Camellia sinensis | Leaf | 8.0 | 12.0 | -0.1 | CRC Handbook of Medicinal Herbs and/or CRC Handbook of Proximate Analyses |
| Canavalia ensiformis | Seed | 1.3 | 1.7 | -0.7 | * |
| Canavalia ensiformis | Fruit | 1.0 | 4.7 | -0.1 | * |
| Canna indica | Root | 0.1 | 0.3 | -0.8 | * |
| Cannabis sativa | Seed | 1.7 | 2.0 | -0.6 | CRC Handbook of Medicinal Herbs and/or CRC Handbook of Proximate Analyses |
| Capparis spinosa | Flower | 0.89 | 2.16 | -1.0 | * |
| Capsella bursa-pastoris | Plant | 1.7 | 14.4 | 0.2 | * |
| Capsicum frutescens | Fruit | 1.0 | 8.0 | 0.6 | * |
| Capsicum annuum | Fruit | -- | 19.0 | 3.0 | * |
| Carica papaya | Leaf | 5.0 | 21.0 | -0.1 | CRC Handbook of Medicinal Herbs and/or CRC Handbook of Proximate Analyses |
| Carica papaya | Fruit | 0.4 | 3.0 | -0.4 | * |
| Carthamus tinctorius | Flower | 0.5 | 3.6 | -0.6 | * |
| Carthamus tinctorius | Seed | 1.0 | 2.0 | -0.6 | * |
| Carum carvi | Seed | 3.0 | 4.0 | 0.2 | USDA's Ag Handbook 8 and sequelae) |
| Carum carvi | Fruit | 3.0 | 4.0 | -0.2 | * |
| Carya illinoensis | Seed | 1.1 | 1.3 | -0.9 | * |
| Casimiroa edulis | Fruit | 0.4 | 3.9 | -0.2 | * |
| Catha edulis | Leaf | -- | 0.5 | -0.2 | * |
| Caulophyllum thalictroides | Root | 1.0 | 7.9 | 0.8 | * |
| Centella asiatica | Leaf | 1.4 | 13.0 | -0.1 | * |