The long slender crystals of polyoxymethylene that grew in irradiated trioxane crystals all grew toward the negative end of the trioxane crystal. The observed direction of growth was consistent with the assumption that the ion at the growing end of the polyoxymethylene chain was a cation. Certain morphological features such as facets and direction of taper of these polyoxymethylene crystals indicated the direction in which the crystals grew. Incidental observations of polyoxymethylene precursor crystals, electret domains in trioxane, and the effects of electron irradiation on polyoxymethylene crystals were made.