  In this paper we at first consider plane trees with the root vertex and a
marked directed edge, outgoing from the root vertex. For such trees we
introduce a new characteristic --- the \emph{parity}, using the bracket code.
It turns out that the parity depends only on the root vertex (not on the marked
edge). And in the case of an even number of vertices the parity does not depend
on the root vertex also. Then we consider rotation groups of bipartite trees,
study their properties and prove that in the case of even number of vertices
rotation groups of even and odd trees are different.
