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).
Prokaryotic reproduction typically involves replication of DNA and binary fission of the cytoplasm to produce two identical offspring. Eukaryotes have a variety of methods of asexual reproduction, including binary fission, budding, fragmentation, spore formation and schizogony.rokaryotic reproduction typically involves replication of DNA and binary fission of the cytoplasm to produce two identical offspring. Eukaryotes have a variety of methods of asexual reproduction, including binary fission, budding, fragmentation, spore formation and schizogony.