VOLUME XLV NUMBER 3 



NEW YORK 



iJO 



Botanical Gazette 



MARCH 1908 



SPERMATOGENESIS, OOGENESIS, AND FERTILIZATION 



IN NEPHRODIUM 

 CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 107 



Shigeo Yamanouchi 



(with PLATES vi-viii) 



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 pteridophytes are already numerous. 

 Historically, however, the motile sperm which first attracted atten- 

 tion was that of the algae, and among them especially the sperm of 

 Chara. 



From the early studies of spermatogenesis in Chara it was gener- 

 ally believed by Nageli (69), Mettenius (62), Hofmeister (38), 

 Strasburger (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 bryophytes and pterido- 

 phytes. 



The first definite statement that the nucleus does not dissolve 

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

 a study of Chara and a number of mosses. He writes that the body 

 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 

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

 of the cytoplasm which envelops that part of the nucleus. 



r-4 145 



