diff --git a/include/boost/container/detail/flat_tree.hpp b/include/boost/container/detail/flat_tree.hpp
index db47562..8106a8b 100644
--- a/include/boost/container/detail/flat_tree.hpp
+++ b/include/boost/container/detail/flat_tree.hpp
@@ -1215,14 +1215,14 @@ class flat_tree
    template<class C2>
    BOOST_CONTAINER_FORCEINLINE void merge_unique(flat_tree<Value, KeyOfValue, C2, AllocatorOrContainer>& source)
    {
-      this->insert( boost::make_move_iterator(source.begin())
+      this->insert_unique( boost::make_move_iterator(source.begin())
                   , boost::make_move_iterator(source.end()));
    }
 
    template<class C2>
    BOOST_CONTAINER_FORCEINLINE void merge_equal(flat_tree<Value, KeyOfValue, C2, AllocatorOrContainer>& source)
    {
-      this->insert( boost::make_move_iterator(source.begin())
+      this->insert_equal( boost::make_move_iterator(source.begin())
                   , boost::make_move_iterator(source.end()));
    }