VOLUME XLV 



NUMBER 3 



Botanical Gazette 



MARCH igo8 



SPERMATOGENESIS, OOGENESIS, AND FERTILIZATION 



IN NEPHRODIUM 



CONTRIBUTIONS PROM THE BX^LL BOTANICAL LABOIL\TORY lo/ 



Shig£o Yamanouchi 



(with plates vi-\-in) 



Historical review 



The pteridophytes have been the source of important contribu- 

 tions to our knowledge of sperms in the plant kingdom, and investi- 

 gations upon spermatogenesis in pteridophvtes are already numerous. 



Chara 



ically, however, the motile sperm which first attracted att( 

 as that of the algae, and among them especiaUv the sperm 



y studies of spermatogenesis in Chara it was , 



Nageli r6o), Mettexius (62), Hofmeistee 



Stil\sburger (83), and Sachs (74) that the nucleus, before the 

 formation of the sperm, dissolves into cytoplasm to form a homo- 

 geneous slimy protoplast from which the body of the sperm is organ- 

 ized. HoFMEisTER, Strasburger, and Sachs held a similar view 

 concerning spermatogenesis in some forms of brj'ophytes and pterido- 

 ph}tes. 



The first definite statement that the nucleus does not dissolve 

 before the formation of the sperm was made by ScHiiiiz (77) from 

 a study of Chara and a number of mosses. He writes that the b<xiy 

 of the sperm is produced by a direct change of form of the nucleus, 

 whose peripheral layer becomes thickened to form a spirally coiled 

 band, while the inner part becomes loose and forms a vesicle. The 

 surface layer of the anterior end of the sperm, bearing cilia, consists 

 of the cytoplasm which envelops that part of the nucleus. 



X4S 



