204 PKOPAGATIOK OF PLANTS. 



In cold climates, the young slender branches of even 

 the most hardy deciduous trees are often injured by the 

 severe frosts of winter ; therefore, when such twigs or 

 branches are wanted for cions, it is best to take them 

 from the parent stock in autumn, soon after the leaves 

 have fallen, and preserve them in earth, saw-dust, char- 

 coal, sand, mqss, or some similar material, where they will 

 be cool not frozen and just sufficiently moist to prevent 

 shriveling. Cions of the^ripe wood of some kinds of trees 

 may be taken from the parent plant in the spring, at the 

 time they are wanted for use ; but their vitality is often 

 weakened by the severity of the weather, and the delicate 

 tissues injured to such an extent that they will not form 

 what is called "granulations" although it is precisely 

 the same as the callus on cuttings which fill up any small 

 interstices that may exist between the stock and cion, al- 

 lowing of the transmission of sap from one to the other. 

 Furthermore, in grafting plants while in a semi-dormant 

 state, it is well to secure as great a difference as practicable 

 in the density of the fluids of the stock and cion, in order 

 to ensure the endosmose and exosmose movement of the 

 sap, as explained in Chapter I., and to secure this condi- 

 tion we have only to keep the branches selected for cions 

 in a dormant state until the sap of the stock has begun 

 to flow in spring. While it cannot be said to be positively 

 necessary in every instance that there should be any con- 

 siderable difference in the density of the fluids of the 

 stock and cion, to insure success in grafting, still, with 

 some kinds of trees, a difference in condition is rather to 

 be sought than otherwise. 



CLEFT GEAFTING. This method is the original or most 

 primitive of all the different modes of grafting trees, and 

 it is principally used upon large stocks or on the brancLes 

 of old trees. It is rather a bungling, unscientific method 

 of grafting, exposing an unnecessary amount of surface 

 to be healed over by a new growth, and the scars made in 



