28 PLANT PROPAGATION 
top should be retained, removing all those that will be 
buried under the soil. Also, any buds that may exist 
between the parent stem and the layered portion should 
be effaced, or at any rate suppressed, otherwise nourish- 
ment would be used up that should go towards building 
up the new plant. 
Twisting. 
The same details are foHowed as above, with the 
addition of giving the portion of the stem to be buried a 
LAYERING BY—(A) TONGUEING OR HEELING, AND (B) RINGING. 
twist to rupture the tissue, and so to check the down- 
ward flow of the sap and thus to aid the emission of 
roots. 
Ringing. 
This method can be understood by referring to the 
illustration. A ring of the outer and inner bark is 
removed. The upward flow of the sap will proceed, but, 
the descent being checked, roots will be emitted. 
Tongueing. 
This is an excellent and widely practised method. It 
consists of making an incision with a sharp knife be- 
