SEED-BEARING PLANTS 



403 



elongates the generative cell passes down it, becoming 

 divided into two sperm-cells. These sperm-cells are 

 remarkably interesting little bodies, bearing a large num- 



FIG. 300. Dioon edule: upper part of an ovule at the time of fertiliza- 

 tion, showing integument, nucellus, male gametophytes (germinating 

 pollen-grains), and female gametophytes (embryo-sacs). Reconstructed 

 from sections of several ovules. (After Chamberlain.) 



ber of cilia, by the motion of which they are carried, in 

 the completion of their journey to the egg, through the 

 watery solution emptied from the pollen-tube, to and 



