Let (baxtn, ♯ ) be the Baxter monoid of finite rank n with Schützenberger's involution ♯ . In this paper, it is shown that (baxtn, ♯ ) admits a faithful representation by an involution monoid of upper triangular matrices over any semiring from a large class including the tropical semiring under the skew transposition. Then a transparent combinatorial characterization of the word identities satisfied by (baxtn, ♯ ) is given. Further, it is proved that (baxtn, ♯ ) is finitely based if and only if n = 3, and shown that the identity checking problem for (baxtn, ♯ ) can be done in polynomial time.