Life   cycle   of   an
   angiosperm (flowering plant).

   A plant alternates between a multicellular diploid (2n) sporophyte and
   a multicellular haploid (n) gametophyte generation.
<Li> A   mature  plant  is  a  multicellular  diploid  sporophyte  with
reproductive structures.
<Li> Anthers  contain  microsporangia  in  which  germ  cells divide by
meiosis to produce microspores.
<Li> Ovaries  contain  megasporangia  in  which  germ  cells  divide by
meiosis to yield 4 megaspores each.
<Li> Microspores   divide   by   mitosis  to  form  multicellular  male
gametophytes (pollen grains), which contain sperm cells.
<Li> One of the 4 megaspores divides by mitosis to form a multicellular
female  gametophyte (embryo sac), which contains an egg cell in an
ovule.
<Li> Fertilization (pollination) occurs when a sperm fuses with an egg,
producing a diploid single-celled zygote.
<Li> The zygote develops by mitosis to produce the sporophyte.