If the spore mother cells are still quite young, we shall find the nucleus (Fig. 127, _A_, _n_) comparatively small, and presenting a granular appearance when strongly magnified. These granules, which appear isolated, are really parts of filaments or segments, which are closely twisted together, but scarcely visible in the resting nucleus. On one side of the nucleus may usually be seen a large nucleolus (called here, from its lateral position, paranucleus), and the whole nucleus is sharply separated from the surrounding protoplasm by a thin but evident membrane. The first indication of the approaching division of the nucleus is an evident increase in size (_B_), and at the same time the colored granules become larger, and show more clearly that they are in lines indicating the form of the segments. These granules next become more or less confluent, and the segments become very evident, appearing as deeply stained, much-twisted threads filling the nuclear cavity (Fig. 127, _C_), and about this time the nucleolus disappears. The next step is the disappearance of the nuclear membrane so that the segments lie apparently free in the protoplasm of the cell. They arrange themselves in a flat plate in the middle of the cell, this plate appearing, when seen from the side, as a band running across the middle of the cell. (Fig. 127, _D_, shows this plate as seen from the side, _E_ seen from above.) About the time the nuclear plate is complete, delicate lines may be detected in the protoplasm converging at two points on opposite sides of the cell, and forming a spindle-shaped figure with the nuclear plate occupying its equator. This stage (_D_), is known as the "nuclear spindle." The segments of the nuclear plate next divide lengthwise into two similar daughter segments (_F_), and these then separate, one going to each of the new nuclei. This stage is not always to be met with, as it seems to be rapidly passed over, but patient search will generally reveal some nuclei in this condition. [Illustration: FIG. 128.--Later stages of nuclear divisions in the pollen mother cell of wild onion, × 350. All the figures are seen from the side, except _B_ ii, which is viewed from the pole.]