  A diffeomorphism $f:\mathbb{R}^2\to\mathbb{R}^2$ in the plane is Anosov if it
has a hyperbolic splitting at every point of the plane. The two known
topological conjugacy classes of such diffeomorphisms are linear hyperbolic
automorphisms and translations (the existence of Anosov structures for plane
translations was originally shown by W. White). P. Mendes conjectured that
these are the only topological conjugacy classes for Anosov diffeomorphisms in
the plane. We prove that this claim holds when the Anosov diffeomorphism is the
time-one map of a flow, via a theorem about foliations invariant under a time
one map.
