174 



Fruits and Seeds. 



Fig. 63. HAIRY BITTERCRESS (Cardaminc hirsuta}. 



II. 



I. The next points to which I will direct your at- 

 tention are the means of dispersion possessed by 

 many seeds. Farmers have found by experience 

 that it is not desirable to grow the same crop in the 

 same field year after year, because the soil becomes 

 more or less exhausted. In this respect therefore 

 the powers of dispersion possessed by many seeds 

 are a great advantage to the species. Moreover, 

 they are also advantageous in giving the seed a 

 chance of germinating in new localities suitable to 

 the requirements of the species. Thus, one com- 



