Pollen grains are formed in the anther of the flower by which sequence of events?Haploid microspore mother cells divide by mitosis to form four diploid microspores. Each microspore develops into a pollen grain by meiosis. Diploid microspore mother cells divide by meiosis to form four haploid microspores. Each microspore develops into a pollen grain by mitosis. Diploid megaspore mother cells divide by mitosis to form four diploid megaspores. Each megaspore develops into a pollen gram by meiosis. Diploid microspore mother cells divide by mitosis to form four haploid microspores. Each microspore develops into a pollen grain by meiosis. Haploid microspore mother cells divide by meiosis to form four diploid microspores. Each microspore develops into a pollen grain by mitosis.