Differential interference contrast (DIC) light micrograph of onion (Allium cepa) meristematic cells during mitosis (nuclear division). Mitosis is the formation of two daughter nuclei from one parent nucleus. At left the cell is in prophase, the nuclear envelope dissolves and the chromosomes (red) condense. Second from left the cell is in metaphase, with the chromosomes aligned along the centre of the cell. The chromosomes start to move to the opposite poles, guided by microtubules, during anaphase (second from right). At right, the cell is in telophase. The separated chromosomes have moved to opposite ends of the cell and two new nuclei form around them. Orcein staining.