As more and more states legalize marijuana, businesses selling the leafy green weed are, um, cropping up. But marijuana still remains illegal under federal law, and that creates a potentially significant problem for entrepreneurs aiming to sell the crop: the inability to register a federal trademark.

Specifically, trademark registration awards the rights to use a particular trademark nationwide, to file for injunctions to stop unauthorized use of trademarks and to file trademark or service mark infringement claims for money damages. Registration also prohibits the importation of goods that might infringe on the trademark. The holder can appeal to U.S. Customs.

But the conundrum is that companies offering certain categories of brands are prohibited from federally registering a trademark at all. And businesses selling marijuana for medicinal and recreational use, as allowed by their state governments, are in just such a category. [Read more at Entrepreneur]