A lawsuit challenges the constitutionality of part of a new state law that requires a coveted medical-marijuana license to go to a black farmer.

Columbus Smith, a black farmer from Panama City, filed the lawsuit, alleging that the law is so narrowly drawn that only a handful of black farmers could qualify for the license. The lawsuit contends that the measure is what is known as an unconstitutional “special law.”

The law, passed during a June special session, was designed to carry out a November constitutional amendment that broadly legalized medical marijuana in Florida. A key part of the law was expanding the number of licenses that would be awarded to operators in what could turn into a highly lucrative industry.