Let $n\in\mathbb N$, let $(M,\omega)$ be a smooth symplectic manifold of dimension $2n$, and let $\Sigma\subset M$ be an embedded smooth codimension-one submanifold. For each $x\in \Sigma$, define
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\begin{align*}
\mathcal L_{\Sigma,x}:=\ker\left(\omega_x|_{T_x\Sigma}\right)=\{v\in T_x\Sigma:\omega_x(v,w)=0\text{ for every }w\in T_x\Sigma\}.
\end{align*}
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Then $\mathcal L_\Sigma=\bigsqcup_{x\in\Sigma}\mathcal L_{\Sigma,x}$ is a smooth rank-one subbundle of $T\Sigma$. Consequently, through every point of $\Sigma$ there is a local one-dimensional foliation by immersed curves whose tangent line at each $x\in\Sigma$ is $\mathcal L_{\Sigma,x}$.