62 j> o s t e I i a 



Nageli's hypothesis effected no percep- 

 tible modification in the prevailing 

 theory which is today generally accepted 

 as portrayed in the following quotation 

 from Goebel's Organography. ' ' I need 

 only say here that the cotyledons, which 

 so frequently differ in form from the foli- 

 age leaves, are merely arrested forms of 

 these, the arrest being sometimes per- 

 manent, sometimes transient." 



Many students of angiospermic em- 

 bryology have recognized difficulties in 

 this interpretation, but have accepted 

 it for want of a better. It is based 

 solely upon the resemblance which the 

 cotyledons of certain seedlings bear to 

 the foliage leaves, while their origin, 

 structure and primary function would 

 seem to disclaim such a relationship ; 

 for the cotyledons do not arise as 

 exogenous lateral outgrowths upon the 

 growing point of a stem, as do all later 



