H G 



/ig. 49. Hydrilla verticil lain, formation of megaspores. .4, hypodermal arche- 

 sporial cell. B, cutting off of primary parietal cell. C, anticlinal division of pri- 

 mary parietal cell. D, ovule at megaspore mother cell stage. E, megaspore 

 mother cell in prophase of Meiosis I ; two other cells of the nucellus lying below it 

 simulate sporogenous cells. F,G, first division of megaspore mother cell resulting 

 in formation of dyad cells. H, tetrad of megaspores. 



70 



