structure of pistil and stamens in the section at the time of double fertilization

anatomy angiosperm anther antipodals background biology botanical botany cell cross diagram diploid double egg embryo english female fertilization filament flora flower gametophyte illustration integument isolated megagametophyte micropyle morphology nucellus nuclei ovary ovule part parts phytomorphology pistil plant polar pollen reproduction sac scheme section stamen stigma structure title vector white