Differential interference contrast (DIC) light micrograph of onion (Allium cepa) meristematic cells, each with four nuclei, during mitosis (nuclear division). Mitosis is the formation of two daughter nuclei from one parent nucleus. At top the cell is in interphase. The nuclei (round) are clearly visible. As the cell moves into prophase (second from top), the nuclear envelopes dissolve and the chromosomes (red) condense. At centre the cell is in metaphase, with the chromosomes aligned in a row. The chromosomes start to move to opposite poles, guided by microtubules, during anaphase (second from bottom). At bottom, the cell is in telophase. The separated chromosomes have moved to opposite sides and eight new nuclei form around them. Orcein staining.