320 



GYMNOSPERMS 



ing nearly all of the passage of the body cell down the tube (fig. 318). 

 As the tube is about to discharge the sperms, the wall of the body cell 

 seems to have disappeared entirely, so that the sperm nuclei are in a 



Fig. 318. — Pollen tubes of Pinus: A, Pimis strohus, two sperms, quite unequal; be- 

 low the two sperms, the nucleus of the stalk cell and a little lower down, the tube nu- 

 cleus; X 236; after Dr. Margaret Ferguson;'"* B, P. laricio; the two-sperm nuclei (m) ; 

 n, nucellus of stalk cell; the other nucleus is the tube nucleus; 5, starch; X500; after 

 Coulter;'^' C, P. laricio; the two-sperm nuclei with no wall of the body cell visible; at 

 the right of each nucleus, a dense mass which might represent a blepharoplast; X500; 

 after Chamberlain.'"^ 



mass of cytoplasm which does not seem to be marked off at all from 

 the general cytoplasm of the pollen tube (fig. 318 C). 



In such a condition, either as an organized cell or as a naked 

 nucleus, the sperms, together with the stalk and tube nuclei, are 

 discharged into the egg. 



