Gametophyte development.
<P>
   The  transfer  of  pollen  from  an  anther  to  a  stigma  results in
   pollination.
<P>
<lI> A microsporocyte in a microsporangium undergoes meiosis to produce
4  haploid  microspores,  which  mature  into  pollen  grains each
containing a generative cell and a tube cell.
<lI> A megasporocyte in an ovule undergoes meiosis to produce 4 haploid
cells,  one of which survives as the megaspore, which matures into
a  multicellular  embryo sac containing one egg cell and two polar
nuclei.