PLANT REPRODUCTION 



97 



apparatus; one is very large and known as the egg or female 

 gamete, while the other two are known as the synergids. The 

 three nuclei at the opposite end of the embryo sac are known as 



FIG. 73. (a) Diagrammatic drawing of stamens and pistil showing longitudinal section 

 of ovule. The pollen tube is entering the micropyle; (6) longitudinal diagrammatic section 

 of ovule showing the formation of the embryo and endosperm. 



the antipodals. The two nuclei in the central part of the sac 

 are known as the polars. 



The pollen tube, to which we have previously referred, hav- 



