| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Cassia tora | Seed | -- | 3180.0 | 0.1 | * |
| Castanea mollisima | Seed | 820.0 | 1531.0 | -0.6 | * |
| Castanea dentata | Seed | 790.0 | 1406.0 | -0.6 | * |
| Castanea sativa | Seed | 320.0 | 704.0 | -0.9 | * |
| Catalpa ovata | Fruit | -- | 1960.0 | -0.1 | * |
| Caulophyllum thalictroides | Root | 143.0 | 1300.0 | -0.7 | * |
| Celosia cristata | Flower | -- | 6080.0 | 2.4 | * |
| Centella asiatica | Leaf | 342.0 | 3200.0 | -0.4 | * |
| Chaenomeles lagenaria | Fruit | -- | 990.0 | -0.5 | * |
| Chamaemelum nobile | Flower | -- | 2920.0 | 0.1 | * |
| Chamissoa altissima | Leaf | 70.0 | 715.0 | -1.3 | Tramil |
| Chenopodium album | Seed | -- | 2920.0 | -0.0 | * |
| Chondrus crispus | Plant | -- | 19600.0 | 4.8 | Pedersen, M. 1987. Nutritional Herbology. Pederson Publishing. Bountiful, Utah. 377 pp. |
| Chrysanthemum parthenium | Leaf | 432.0 | 2400.0 | -0.7 | * |
| Chrysanthemum parthenium | Plant | -- | 2400.0 | -0.5 | * |
| Chrysanthemum coronarium | Bud | 170.0 | 2285.0 | 1.0 | * |
| Cicer arietinum | Seed | 1110.0 | 1348.0 | -0.6 | USDA's Ag Handbook 8 and sequelae) |
| Cichorium intybus | Root | 220.0 | 1100.0 | -0.8 | * |
| Cichorium intybus | Leaf | 130.0 | 2652.0 | -0.6 | USDA's Ag Handbook 8 and sequelae) |
| Cichorium endivia | Leaf | 95.0 | 2400.0 | -0.7 | * |