The crystal structure of the distorted-fcc high-pressure phase of the rare-earth elements is discussed in connection with the Landau theory of phase transition. From x-ray-diffraction spectra the irreducible representation ${\mathit{E}}_{\mathit{u}}^{\mathit{L}}$ is found to drive the (almost) continuous transition fcc\ensuremath{\rightarrow}distorted fcc. Using just symmetry arguments four structures induced by ${\mathit{E}}_{\mathit{u}}^{\mathit{L}}$ are compatible with the x-ray-diffraction pattern; but only one (space group Cmmm, Z=8) can have a continuous transition to fcc.