| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Crataegus rhipidophylla | Bark | -- | -- | * | |
| Crataegus laevigata | Bark | -- | -- | * | |
| Crocus sativus | Silk Stigma Style | -- | -- | * | |
| Croton tiglium | Seed | 900.0 | 1500.0 | -0.5 | * |
| Cryptostegia grandifolia | Seed | -- | 10240.0 | -0.3 | * |
| Cucumis sativus | Seed | 11100.0 | 69785.0 | 0.9 | * |
| Cucumis melo | Seed | 10080.0 | 35145.0 | 0.2 | * |
| Cucumis sativus | Fruit | 30.0 | 759.0 | -0.2 | * |
| Cucumis melo | Cotyledon | 10100.0 | 61400.0 | -0.6 | * |
| Cucumis sativus | Cotyledon | 28800.0 | 59100.0 | -0.6 | * |
| Cucurbita pepo | Fruit | 30.0 | 357.0 | -0.3 | USDA's Ag Handbook 8 and sequelae) |
| Cucurbita foetidissima | Seed | 2430.0 | 28475.0 | 0.1 | * |
| Cucurbita spp | Fruit | 40.0 | 635.0 | -0.2 | * |
| Cucurbita pepo | Flower | 20.0 | 410.0 | 0.9 | USDA's Ag Handbook 8 and sequelae) |
| Cucurbita pepo | Seed | 22670.0 | 30710.0 | 0.1 | * |
| Cucurbita maxima | Seed | -- | 21450.0 | -0.1 | * |
| Cyamopsis tetragonoloba | Seed Oil | -- | 58000.0 | -0.5 | Varade, P. B., Misra, B. K., Sikka, K. C., Singh, S. P. 1984. Nutritive Assessment of Guar Oil (Cyamopsis tetragonoloba L. Taub). J Agr Food Chem, 32(5): 1073-1075. |
| Cynara cardunculus | Flower | 30.0 | 200.0 | -1.7 | USDA's Ag Handbook 8 and sequelae) |
| Cyperus rotundus | Rhizome | -- | -- | * | |
| Datura stramonium | Plant | -- | -- | * |