Crystal structures and orientation effects in cerium (Ce) metal were investigated in the pressure range of 028 GPa by high-resolution synchrotron x-ray diffraction using image plate technique with a diamond-anvil cell. We observe crystal grain growth during the phase transformations to -uranium structure both during compression and decompression cycle. We offer explanation for the long-standing controversy on the intermediate phases and attribute various crystal structure proposals to low-resolution and orientation effects. This crystal grain growth during phase transformation in Ce at high pressure and ambient temperature is an unusual phenomenon among metals. © 1995 The American Physical Society.