62 PROPAGATION BY DIVISION. [CHAP. IV. 



that wounds or injures the shoot, so as to throw 

 an impediment in the way of the returning sap, 

 and yet not to prevent the passage of the sap 

 that is ascending, will suffice. 



Layering is a very common mode of pro- 

 pagating plants ; and in nurseries often every 

 shoot of a tree or shrub is thus wounded and 

 pegged down. In this case, the central root is 

 called a stool, from the verb to stole, which 

 signifies the power most deciduous trees possess, 

 of sending up new stems from the collar of 

 their roots when cut down. The seasons for 

 performing the operation of layering are during 

 the months of February and March, before the 

 new sap begins to rise, or in June or July, after 

 all the summer supply of ascending sap has 

 risen ; as at these seasons there is no danger of 

 injuring the tree by occasioning an overflow of 

 the ascending sap, which sometimes takes place 

 when the tree is wounded while the sap is in 

 active motion. In most cases the layers are 

 left on twelve months, and in many two years, 

 before they are divided from the parent plant, 

 in order that they may be sufficiently supplied 

 with roots. In nurseries, the ground is gene- 

 rally prepared round each stool by digging, and 

 sometimes by manuring ; and the gardener 

 piques himself on laying down the branches 

 neatly, so as to form a radiated circle round 

 the stool, with the ends rising all round about 

 the same height. 



Chinese mode of layering. — The Chinese 

 method of layering, which consists in wounding 

 a branch, and then surrounding the place with 

 moist earth contained either in a flower-pot or 



