The nucleus in the powdery mildew cell may move before, during, and after division. Sometimes the nucleus was surrounded by several membranes and sometimes microtubules which originated in the spindle plaque and fanned out into the cytoplasm. Long straight or undulating strands, about 0.5–1 μ, in width and many microns in length composed of microtubules or laminated membranes, were observed in Erysiphe graminis cells in which nuclei move, but were not observed in conidia, where nuclei remain stationary. The end of the strand, sometimes, was attached to the nuclear membranes, and other times extended past the nucleus. It is postulated that the strands, astral microtubules, and spindle plaques are associated with controlled nuclear movement which is independent of cytoplasmic streaming.