li 



surface is covered by a fine reticulation (Fie 10). 

 An equatorial section shows tliat the intine is strong- 

 ly developed under the furrows, which r;ives the sec- 

 tion of tlie interior a decidedly three-lobed appear- 

 ance. (Figs. 11, 12). 



Soon after the pollen <";rain is freed from the moth- 

 er-cell its nucleus divides, and the smaller nucleus 

 which is here called the c-nerative nucleus in accord- 

 ance with other Angiosperms, retires into the extremity 

 of one of the lobes. Here it becomes closely applied 

 to the intine and is cut off from the larger cell by 

 a very noticeable wall, which is probably of cellulose 

 (Fig. 11). Shortly before the pollen is shed this 

 wall disappears, and the two nuclei then lie free in 

 the cavity of the grain. The larger of the two, the 

 tube nucleus, is loosely vesicular^ while the struc- 

 ture of the generative m^cleus is dense and deeply 



