URAL LIBRARY SERIES. 



Cross-Breeding and Hybridizing. 



THE PHILOSOPHY OF THE CROSSING OF PLANTS, CONSID- 

 ERED WITH REFERENCE TO THEIR IMPROVE- 

 MENT UNDER CULTIVATION. 



IT is now understood that the specific forms or groups of plants have been 

 determined largely by the survival of the fittest in a long and severe 

 struggle for existence. The proof that this struggle everywhere exists 

 becomes evident upon a moment's reflection. We know that all organisms 

 ari eminently variable. In fact, no two plants or animals in the world are 

 exactly alike. We also know that very few of the whole number of seeds 

 which are produced in any area ever grow into plants. If all the seeds pro- 

 duced by the elms upon Boston Common in any fruitful year were to grow 

 im«-o trees, this city would become a forest as a result. If all the seeds of 

 arest orchid in our woods were to grow, in a few generations of plants 

 l our farms would be overrun. If all the rabbits which are born were 

 * ~h old age and all their offspring were to do the same, in less than 

 X, rs every vestige of herbage would be swept from the country and our 

 , would become barren. There is, then, a wonderful latent potency 

 1 se species ; but the same may be said of every species of plant and 

 •' , even of man himself. If one species of plant would overrun and 

 ■ e land if it increased to 'the full extent of its possibilities, what 

 _ >~ 3 the result if each of the 2, 061 plants known to inhabit Middlesex 

 were to do the same ? And then fancy the result if each of the ani- 

 i, from rabbits and mice to frogs and leeches, were to increase without 

 :k ! The plagues of Egypt would be insignificant in the comparison ! 

 fact is, the world is not big enough to hold the possible first offspring of 

 > ; ilants and animals at this moment living upon it. Struggle for existence, 



