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A TEXTBOOK OF THEORETICAL BOTANY 



sporangial wall. The cells of the tapetum disorganize and a nucleated mass 

 of protoplasm results, which envelops the spores. The spores move to the 



Sporangium wall 



Swimming apparatus 



Megaspore 



Fig. 556. — Azolla filiculoides. Longi- 

 tudinal section of a megasporan- 

 gium. The megaspore wall is 

 somewhat collapsed. 



periphery, and the tapetal plasmodium develops a number of vacuoles in 

 which the spores are grouped in approximately equal numbers. Then each 







>> 



S>^ / 



\- 



:>-^c 



Indusium 





-^ " ft .."jiX y-- -^^T ' — ' " i " •" " ' Massula 





Fig. 557. — Azolla filiculoides. Transverse section of a 

 microsorus with a large number of microsporangia 

 containing massulae. 



