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A TEXTBOOK OF THEORETICAL BOTANY 



FIRST PROTHALLIAL 

 CELL 



ANTHERIDIAL 

 CELL 



AIR SACS 



STALK 

 CELL 



BODY CELL 



FIRST PROTHALLIAL 

 CELL 



SECOND PROTHALLIAL 

 CELL 



ANTHERIDIAL 

 CELL 



FIRST PROTHALLIAL 

 CELL 



SECOND 

 PROTHALLIAL 



CELL 



ANTHERIDIAL 

 CELL 



TUBE 

 NUCLEUS 



Fig. 682. — Pinits sylvestris. Development of the male gametophyte. A, Division of 

 microspore mother cell. B, Completed tetrad of microspores with the mother cell. 

 C, Mature microspore. D, Formation of first prothallial cell. E and F, Formation 

 of second prothallial cell. G, Division of antheridial cell to form stalk cell, body 

 cell and tube nucleus. Compare with Fig. 683. {After Coulter and Chamberlain.) 



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