CYCADALES 



143 



(fig. 166). The blepharoplast is surrounded by a beautiful system 

 of radiations, so that the whole structure has exactly the appearance 

 of a centrosome with its aster. In Dioon edule, during early stages, 

 the rays appear very coarse on account of globules which become 





160 



161 



/ 



162 



Figs. 160-165. — Cycas revoluta: fig. 160, pollen grains at shedding stage; X500, 

 fig. 161, later stage, showing prothallial cell {p) and generative cell {g), the tube nucleus 

 not .shown; X200; fig. 162, generative cell divided, giving rise to stalk and body cells; 

 X500; fig. 163, the stalk nucleus {s) being crowded out, and blepharoplasts appearing 

 in the body cell (&); X500; fig. 164, the body cell shortly before division, showing two 

 well-developed blepharoplasts; X750; fig. 165, the two male cells resulting from the 

 division of the body cell; the beaks of the nuclei are attached to the cilia-bearing 

 bands; X200. — After Ikeno (27). 



attached and spread along them (fig. 159); later they become smooth 

 and even. During the earlier stages in the development of the body 

 cell, when it is more or less elongated in the direction of the long axis 

 of the pollen tube, the blepharoplasts lie in the plane of the long axis; 

 but as the pollen tube enlarges, the body cell gradually becomes nearly 



