THE ORIGIN OF SEX IN PLANTS 27 



unequal gametes fuse intimately, and the resulting zygote 

 is the starting point for a new Fern. Thus syngamy in 

 a Fern consists in the fusion of two cells differing in 

 character, and derived from distinct sources, to form a 

 zygote which grows into a new individual. The one is 

 a large non-motile egg, the other is a small motile sperma- 

 tozoid. In its essential features this corresponds to what 



V 



FIG. 14 bis. 



Section of an egg of a Fern, showing the spirally coiled male nucleus 

 within the female nucleus, and fusing with it. Twelve hours after 

 fertilization, (xiaoo. After Shaw.) 



is seen in simpler plants, though the details and accessories 

 are different. 



In Flowering Plants the accessory circumstances are 

 again different, though the essentials are the same. The 

 parts which produce the sexual cells are grouped in that 

 complex structure known as the Flower. The most showy 

 parts of the flower, the petals, take no direct part in 

 reproduction. It is the parts that lie within the petals, 

 viz. the stamens and carpels, which produce the gametes 



