114 Principles of Plant Culture. 



the tree. With poorly-matured wood the reverse is the 

 case. In a few deciduous trees, as the beech and some 

 oaks, many of the mature leaves remain on through the 

 winter. 



174. Hardiness Depends upon the Degree to which 

 the Dormant State is Assumed. Since the most se- 

 vere climatic extremes come during the natural rest 

 period of plants the ability of the plant to endure these 

 extremes depends upon the extent to which the pro- 

 toplasm becomes dormant during the decline of growth. 

 As a rule, a given plant is hardy (10) in a locality 

 in which the duration and the warmth of the growing 

 season are sufficient to complete and fully mature its 

 normal amount of growth. Varieties of the apple and 

 other trees, that so far complete their growth in any 

 given locality that their leaves fall before hard frosts, 

 are rarely injured in winter, while those that continue 

 growth until their foliage is destroyed by freezing suf- 

 fer in severe winters. Deciduous trees are liable to 

 destruction in severe winters in a climate where none of 

 the leaves fall before hard frosts, as is the case with 

 the peach, apricot and nectarine in northen United 

 States. 



175. Individual Plants Cannot Adjust Themselves 

 to a New Environment, except to a slight extent. The 

 power to complete the annual growth processes and be- 

 come sufficiently dormant to endure the rigor of the 

 rest period in any given locality is inherited, and not 

 acquired. We are, therefore, able to do very little 

 toward inuring or acclimatizing (ac-cli'-ma-tiz-ing) in- 

 dividual plants to an environment to which they were 



