| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Carthamus tinctorius | Seed | 200000.0 | 626000.0 | 1.9 | * |
| Carum carvi | Fruit | 127000.0 | 176826.0 | 0.7 | * |
| Carum carvi | Seed | 100000.0 | 180000.0 | -0.4 | * |
| Carya illinoensis | Seed | 712000.0 | 753000.0 | 2.6 | * |
| Casimiroa edulis | Seed | 4000.0 | 8000.0 | -1.4 | CRC Handbook of Medicinal Herbs and/or CRC Handbook of Proximate Analyses |
| Casimiroa edulis | Fruit | 300.0 | 22222.0 | -0.5 | * |
| Cassia tora | Seed | 33000.0 | 74000.0 | -1.0 | * |
| Cassia tora | Plant | -- | 44000.0 | -0.1 | * |
| Castanea sativa | Seed | 16000.0 | 36520.0 | -1.2 | * |
| Castanea dentata | Seed | 12600.0 | 24208.0 | -1.3 | * |
| Castanea sativa | Leaf | -- | 81000.0 | 0.5 | * |
| Castanea mollisima | Seed | 10600.0 | 20648.0 | -1.3 | * |
| Castanospermum australe | Seed | -- | 7000.0 | -1.4 | * |
| Catalpa bignonioides | Seed | 44000.0 | 330000.0 | 0.3 | * |
| Catha edulis | Seed | -- | 500000.0 | 1.2 | * |
| Caulophyllum thalictroides | Root | 660.0 | 6000.0 | -0.6 | * |
| Cedrela odorata | Seed | -- | 214000.0 | -0.3 | * |
| Cedrus deodora | Seed | -- | 447000.0 | 1.0 | * |
| Ceiba pentandra | Seed | 200000.0 | 400000.0 | 0.7 | * |
| Celosia cristata | Seed | -- | 134000.0 | -0.7 | * |