chap, rv.] 



LAYERS. 



61 



FIG. 5. A VERBENA. LAYERED. 



The only art required in layering is to con- 

 trive the most effectual means of interrupting 

 the returning sap, so as to produce as great 

 an accumulation of it as possible at the joint 

 from which the roots are to be produced. For 

 this purpose, sometimes, instead of cutting the 

 branch half through, a ring- of bark is removed 

 below the joint, care being taken that the knife 

 does not penetrate into the wood ; and at others 

 a wire is twisted firmly round the shoot, so as 

 to pinch in the bark ; or a knife or other sharp 

 instrument is passed through the branch several 

 times in different directions : in short anything 



