The director of each division shall be its executive and administrative head, subject to the supervision and control of the secretary of agriculture, and the signature of each director to any executive or administrative order within the scope of his duties shall be a sufficient authority therefor; but the board may, by rule or regulation, prescribe the limits within which any division director may act without the sanction and approval of the secretary or the board itself.
N.J.S. § 4:1-18