GINKGOALBS 



47 



the archegonial chamber after the development of the endo- 

 sperm beak is not made clear in Hirase's account, which seems 

 to imply that the way is open to the archegonial chamber. In 

 any event, the sperms reach the chamber, and in it Hirase has 



Fio. 34 — GinTcgo biloba : A, longitudinal section of the neok of the archegonium, x 160 ; 

 B, transverse section of the same, x 160 ; C, archegonium shortly before fertilization, 

 showing ventral canal cell {v) and q^^ nucleus (?i), x 66 ; Z), free nuclei resulting 

 from the first nuclear divisions of the oospore, x 66 ; ^, later stage, showing the 

 compact tissue of the embryo tilling the oospore, x 66. — After Steasbcegee. 



observed them swimming. The entrance of sperms into the 

 archegonia follows, and fertilization is effected. 



The statement has been usual that fertilization does not 

 occur until the ripe ovules have fallen. While this may be 

 true frequently, Hirase found that some seeds, at least, con- 



