Let M S f low (M n , k) and M S dif f (M n , k) be MorseSmale flows and diffeomorphisms respectively the non-wandering set of those consists of k fixed points on a closed n-manifold M n (n ≥ 4). We prove that the closure of any separatrix of f t ∈ M S f low (M n , 3) is a locally flat n 2 -sphere while there is f t ∈ M S f low (M n , 4) the closure of separatrix of those is a wildly embedded codimension two sphere. For n ≥ 6, one proves that the closure of any separatrix of f ∈ M S dif f (M n , 3) is a locally flat n 2 -sphere while there is f ∈ M S dif f (M 4 , 3) such that the closure of any separatrix is a wildly embedded 2-sphere.