18 STEM. 



one to one and a half degrees higher in tem- 

 perature than the atmosphere, but in tropical 

 climates the earth is many degrees hotter. 

 The system of applying bottom heat to accele- 

 rate the junction of the parts of plants that have 

 been grafted, budded, or inarched, is successful 

 from its exciting the healthy and rapid action 

 of the roots in absorbing juices and supplying 

 them in abundance to the stock. 



The root is never entirely dormant except 

 when frozen ; during the winter it is slowly col- 

 lecting juices for the supply of the spring; 

 where the period of rest or winter is long, the 

 store of juices is large, and vegetation in the 

 spring is rapid and luxuriant. This accounts for 

 the quick growth in northern climates where 

 plants commence vegetation and mature their 

 fruit in the short space of three months. 



Stem. 



The stem is that part of a plant which is 

 developed above-ground, and which took an 

 upward direction at the period of germination 

 of the seed. 



It consists of a woody axis, covered by bark 

 having pores on its surface, bearing leaves with 



