diff --git a/src/localgeodesicfestiffness.hh b/src/localgeodesicfestiffness.hh
index 09e792078ed90da60c19cc5ee52897bbc5000ff7..8224b8bdf01f6e15340a3a5ec89c512f6a83e482 100644
--- a/src/localgeodesicfestiffness.hh
+++ b/src/localgeodesicfestiffness.hh
@@ -85,7 +85,9 @@ public:
     virtual RT energy (const Entity& e,
                        const std::vector<TargetSpace>& localSolution) const = 0;
 
-    /** \brief Assemble the element gradient of the energy functional */
+    /** \brief Assemble the element gradient of the energy functional 
+
+    The default implementation in this class uses a finite difference approximation */
     virtual void assembleGradient(const Entity& element,
                                   const std::vector<TargetSpace>& solution,
                                   std::vector<Dune::FieldVector<double,blocksize> >& gradient) const;