THE MICROSPORANGIUM 



47 



E F G H I 



Fig. 36. Development of microspores and male gametophyte of Halophila ovata. 

 A, l.s. of young staminate flower. B, microspore mother cells with a few tapetal 

 cells t. C, chains of microspores; note vacant spaces x separating individual 

 tetrads. D, single microspore. E, microspore, showing tube and generative 

 cells. F, older stage, showing spindle-shaped generative cell lying inside vegeta- 

 tive cytoplasm. G, pollen grain, showing division of generative cell. H , same, 

 more advanced stage. Note formation of constriction furrow across generative 

 cell. I,J, formation of sperm cells completed. K,L, division of generative cell, 

 showing formation of transitory cell plate. (After Kausik and Rao, 194%.) 



