ANGIOSPERMS 



443 



C. The Male Gametophyte. — What was said about the 

 male gametophyte of gymnosperms applies here as well. 

 This generation in angiosperms is composed of only three 

 cells, two of which are sperm cells; it is hidden within 

 the pollen grain and later in the tube which grows from the 

 pollen grain. 



D. The Female Gametophyte. — Here we find a difference. 

 What was said about this structure as to gymnosperms will 

 not do as to angiosperms. 

 Though very small among 

 gymnosperms, the female 

 gametophyte is even 

 smaller among flowering 

 plants. When ready for 

 fertilization it is composed 

 of only eight cells. To 

 observe it we must ex- 

 amine under the micro- 

 scope thin sections taken 

 through young ovules. 

 Look at Figure 228. In 

 it you see how the young 

 ovules lie in a cross sec- 

 tion of a lily ovary. You 

 see a little oval near the 

 center of each ovule. 

 That indicates the female 

 gametophyte. Now study Figure 230. It shows one ovule 

 greatly enlarged. In the female gametophyte which, it con- 

 tains you can count eight cells. There is a group of three 

 at the lower end, the end nearest the opening or micropyle 



Fig. 230. — Longitudinal section through a 

 mature ovule, showing a mature female 

 gametophyte as it lies within the nucellus. 

 This ovule has an outer and two inner 

 integuments. See context. Note the 

 micropyle between the two inner integu- 

 ments. 



