We define sink marks for branched complexes and find conditions for them to determine a branched surface structure. These will be used to construct branched surfaces in knot and tangle complements. We will extend Delman's theorem and prove that a non-2-bridge Montesinos knot K has a persistently laminar branched surface unless it is equivalent to K(1/2q 1 , 1/q 2 , 1/q 3 , −1) for some positive integers q i . In most cases these branched surfaces are genuine, in which case K admits no atoroidal Seifert fibered surgery. It will also be shown that there are many persistently laminar tangles.