  Including the previously untreated borderline cases, the trace spaces in the
distributional sense of the Besov--Lizorkin--Triebel spaces are determined for
the anisotropic (or quasi-homogeneous) version of these classes. The ranges of
the trace are in all cases shown to be approximation spaces, and these are
shown to be different from the usual spaces precisely in the previously
untreated cases. To analyse the new spaces, we carry over some real
interpolation results as well as the refined Sobolev embeddings of J.~Franke
and B.~Jawerth to the anisotropic scales.
