36 PEOPAGATION or PLAWTS. 



form new cells and buds, which may or may not, accord- 

 ing to circumstances, become a new plant. Botanists 

 have been inclined to pass over the adventitious bud as 

 a thing rarely occurring, and then merely a chance pro- 

 duction, consequently not of sufBcient moment to call 

 for any special attention, but to the propagator of plants 

 it has become of great importance wherever and when- 

 ever it can be made available in the multiplication of 

 valuable species and varieties. 



OHAPTEK IV. 

 ROOTS AND THEIR FUNCTIONS. 



In many of the simple plants no organs corresponding 

 to the true roots of the higher orders are produced, the 

 nutrient elements being absorbed directly through all 

 parts of tlie plant alike. At what point in the ascending 

 scale the true roots first appear has not been fully deter- 

 mined, but these organs most probably follow, or are co- 

 existent with, the inception of a division of cells into 

 groups, each possessing special functions, as found in all 

 compound plants. 



As soon as a plant has advanced upward in the scale, 

 and reached a plane where different organs are evtolved 

 with distinct and special functions, roots become neces- 

 sary to its existence, and are consequently among the 

 first of a multiplicity of organs to appear. It is true, if 

 we consult the writings of our most eminent vegetable 

 physiologists, we find that they do not agree as to what 

 part or how much of certain plants should be designated 

 as roots. In the funguses, such as mold and mildew, as 

 well as in the larger mushrooms, the filmy threads called 

 mycelium answer the purpose of true roots, producing 



