Castor beans are back in California, at least as the latest research crop that University of California, Davis Cooperative Extension biofuels guru Steve Kaffka is looking at as a possible source crop for making biofuels. Castor's main toxic protein, ricin, is so potent that a single milligram is sufficient to kill an adult.

For more, see: Castor an oilseed crop that can cure, kill you