144 



MORPHOLOGY OF GYMNOSPERMS 



spherical and the blepharoplasts rotate through 90°, so that they 

 become transverse to the long axis of the tube (tigs. 159-169). The 

 body cell divides in the plane of the long axis of the tube, giving rise 

 to two sperm mother cells. As division of the body cell approaches, 





6J^^ 



^^: 



156 



■^.-'* > 



^=s^: 



168 



169 



Figs. 166-169. — Zatnia floridana: fig. i66, end of pollen tube with prothallial 

 and stalk cells, and the body cell with young blepharoplasts; fig. 167, later stage, 

 showing blepharoplasts in fore and aft position; fig. 168, division of body cell; in 

 section the blepharoplasts appear as broken circles; fig. 169, the two cells resulting 

 from the division of the body cell; the blepharoplast elongating into a band. — After 

 Webber (32). 



the blepharoplast becomes very much vacuolated, and during the 

 division it breaks up into a large number of granules which fuse 

 together and thus initiate the formation of a spiral band (figs. 168, 

 169). While the band is being formed, it is intimately connected 

 with the nucleus (fig. 165), and when completed it is a spiral of five 

 or six turns, lying just below the surface and giving rise to numerous 



