It shall be unlawful for any person, acting either as principal or agent, to sell to any person any fruit trees or other plants representing same to be of a certain kind, variety and description and thereafter to deliver to such purchaser in filling such order and in completing such sale a fruit tree or fruit trees of a different kind, variety or description than the kind, variety or description of such fruit tree or fruit trees so ordered and sold; provided, that a variation in kind, variety and description may vary not more than five percent in any shipment containing not less than 50 such fruit trees.