California Gov. Gavin Newsom has vetoed a bill aimed at decriminalizing the possession and use of some hallucinogens, including psychedelic mushrooms. The veto Saturday comes after the Legislature voted to make California the third state to do so. The bill would have removed criminal penalties for the possession and use of psychedelic mushrooms, mescaline and dimethyltryptamine, or DMT. It would only have applied to those older than 21 years old. It wouldn’t have legalized the sale of the substance. Criminal justice advocates and veterans supported the bill, saying it would destigmatize treatments for PTSD.