©ostelsia 65 



from this pseudo to the truly dicoty- 

 ledonous habit would be brought about 

 by the continued earlier cessation of 

 growth along the median line, and 

 finally its complete localization in the 

 wings of the cotyledon, i, e., on either 

 side of the plumule. The monocoty- 

 ledonous condition would then be con- 

 sidered the more primitive, and the 

 question would now arise as to the 

 ancestral origin of this structure in the 

 Monocotyledons themselves. 



The function of the cotyledon in 

 the Monocots is pre-eminently that of 

 a nursing organ to absorb the food- 

 materials from the endosperm and turn 

 them over to the use of the growing 

 embryo, as illustrated in the germina- 

 tion of corn, cocoanut and others. 

 Primarily it is an embryonic organ, 

 and its phylogenetic origin should be 

 looked for in simpler types of embryos. 



