After microsporogenesis, four pollen grains are formed from one microspore mother cell. They are arranged in the form of a tetrad. More commonly in dicots, the meiotic division produces a tetrahedral tetrad in which microspores are arranged in a tetrahedral form. In monocots, there is a successive type of meiotic division producing isobilateral tetrad in which the pollen grains are arranged laterally to each other.