Minn. Stat. § 333.26: MUST USE U.S. PATENT AND TRADEMARK OFFICE SYSTEM.

For convenience of administration of sections 333.18 to 333.31, but not to limit or extend the applicant's or registrant's rights, the secretary of state shall adopt the classification system in effect in the United States Patent and Trademark Office, and shall revise this classification system to conform with the United States Patent and Trademark Office system as and if changes are made in that system. A single application for registration of a mark may include any or all goods or services with which the mark is actually being used comprised in a single class, but in no event shall a single application include goods or service with which the mark is being used which fall within different classes.