Minnesota has joined the ranks of states where marijuana is a legal medicine. Governor Dayton on Thursday signed legislation that allows the use of a marijuana derivative for medical purposes. Minnesota’s restrictive medical marijuana program has tight controls over qualifying conditions and the form its available in. People won’t be able to smoke it legally or access it in leaf form. The compromise bill upset some medical marijuana advocates, who say many people who need relief won’t get it. But legislative backers say it is a positive first step that satisfied concerns of law enforcement and doctor groups. The law also sets up a task force to assess the impact of medical cannabis. If all goes as planned, the drug will be available in pill and oil form in mid-2015.