The aura can be in the form of prismatic colors, flashes of light, and sometimes stars. They usually last about 20 minutes and then go away. If these flashes or lines of light occur without a headache, it is called an ophthalmic migraine, or a migraine without a headache.
In gymnosperms and flowering plants, the megaspore is produced inside the nucellus of the ovule. During megasporogenesis, a diploid precursor cell, the megasporocyte or megaspore mother cell, undergoes meiosis to produce initially four haploid cells (the megaspores).
Somatic (body) cells do not undergo meiosis because the products of their division will not take part in fertilization. They divide by mitosis, which produces daughter cells with the same number of chromosomes as the parental cell. Mitosis occurs during growth, replacing damaged cells and asexual reproduction.