Mich. Comp. Laws § 286.210
Every dealer within the meaning of this act, engaged in the buying and selling of nursery stock in this state, shall secure a license and certificate, first certifying to the director in writing that he will buy and sell only stock which has been duly inspected and certified by the director, or by an inspector approved by the director, and that he will maintain with the director a list of all sources from which he secures his stock. Dealers or nurserymen distributing nursery stock directly or on a consignment basis from more than 1 store or place of business, sales ground or heeling-in ground, or selling nursery stock from motor vehicles or other vehicles traveling about the state, shall secure a license for each place or each traveling vehicle from which nursery stock is sold or distributed, and the licensees described in this section shall pay the inspection fees as provided in this act for each such place.
MCL 286.210