The mesh on the left is before morphing; the mesh on the right is after morphing.  The icon for radial+linear symmetry is a 3-D wedge lying perpendicular to the selected axis with its vertex at the symmetry system origin.  The highlighted handle is moved.  Note how the handles act on the mesh as if they were planes parallel to and extending away from the selected axis.  This type of symmetry is the equivalent of using both radial and linear symmetry together and is very useful for making radial changes to solid meshes.