xii Contents 



CHAPTER PAGE 



XVI. THE METHOD OF ORIGIN OF NEW SPECIES AND STRUCTURES, AND THE 

 CAUSES OF THEIR FITNESS TO THE PLACES THEY LIVE IN. (Evolution 



and Adaptation) 403 



XVII. THE REMARKABLE IMPROVEMENT MADE IN PLANTS BY MAN, AND THE 



WAY HE BRINGS IT ABOUT. (Plant breeding) 426 



XVIII. THE PRINCIPAL GROUPS INTO WHICH PLANTS NATURALLY FALL, 



WHETHER BY RELATIONSHIP OR HABIT. (Classification) 445 



INDEX. . . . 467 



