SEEDS AND FRUITS 175 



The fruit of the Xanthium then is not only fur- 

 nished with a device for securing transportation 

 from any animal that touches its fruits, but after 

 the fruits have reached a spot favorable for growth, 

 only half the seeds are germinated, the remainder 

 •being held in reserve for a second attempt which 

 may be more successful than the first. Thus, if at 

 this moment every plant of this species were de- 

 stroyed, there would still remain the second seeds of 

 the fruits which have sent up but one plantlet and 

 kept the other in the form of a seed. 



216. JTie apjjle. — The fruit of the apple offers 

 a most interesting study, not only on account of the 

 structiu:e, but also because of the manner in which 

 it has succeeded in attracting the attention of ani- 

 mals, particularly man, and has thus secured dis- 

 semination over an immense area of the earth's 

 surface. During this process it has also undergone 

 great changes as a result of the methods of cultiva- 

 tion by which it has been grown. 



In the examination of the flower of the apple it 

 was seen that the ovary was imbedded in a small 

 greenish capsule, and that the parts of the flower ap- 

 peared to stand on top of it (§ 202). All of the parts 



