424 



GYMNOSPERMS 



sperm nuclei are formed from the body cell, while the tube is still 

 only about half-way through the nucellus. According to Thomp- 

 SON,*^^" the two sperm nuclei differ somewhat in size, and the smaller 

 one may disorganize before the sperms are discharged. Lotsy"' 



u^; 



Fig. 395. — Gnetum: A-E, G. gnemon; F, G, G. moluccense: A, upper part of feiiiak" 

 gametophyte in free nuclear condition, with two eggs (c), and pollen tube with tube nu- 

 cleus (/) and two sperm nuclei (m); B, fertilized egg (fe) surrounded by free nuclei; C, 

 topographic sketch showing position of B;fe, fertilized egg; p, mass of protoplasm sur- 

 rounding theegg;e«</, cellular part of the female gametophyte; D, two cells (proembryo, 

 pe) resulting from first division of fertilized egg; E, suspensor developing from proem- 

 bryo cell; F, end of suspensor with four nuclei which will give rise to the embryo, 

 emb; G, young embryo. A, B, X400; C, Xioo; D, E, X300; F, X2cxj; G, Xso. — 

 After Thompson.'Jo 



