The sale of marijuana for recreational use began in Oregon on Thursday as it joined Washington state and Colorado in allowing the sale of a drug that remains illegal under U.S. federal law. Oregon residents 21 years and older can buy up to a quarter-ounce (seven grams) of dried flowers at roughly 200 existing medical-use marijuana dispensaries as a new law took effect that backers hope will help curb a flourishing black market. Sue Vorenberg, a former cannabis industry worker and editor of the Cannabis Daily Record said, “You can get all the best strains from Oregon, which can make this into a top tourist spot.”