ON PLANT PROPAGATION. 95 1 



these may be cut in very small parts,, each of which will produce 

 a young shoot if submitted to the required conditions. These 

 root-divisions should be placed in pans or boxes, as close as 

 possible, in a very light soil; or sometimes only fibre or sand 

 need be used. The receptacles must be placed on a certain 

 amount of bottom-heat, to enable the young shoots to break 

 easily. As soon as they begin to grow, and have made both 

 roots and leaves, they must be potted separately in suitable soil, 

 and replaced in heat until rooted, when they may be treated 

 as ordinary plants. Many Dahlias possess several fleshy tuber- 

 like roots, which may be separated singly for propagation, allowing 

 one shoot to each, as shown in Fig. 617. Numerous other 

 plants possessing the same characteristics can also be propagated 

 by the above means. 



Layering. 



This is one of the oldest methods of propagation, 

 and also one which is often seen under really natural con- 

 ditions. By this operation a branch is enabled to make roots 

 without being separated from the parent plant. It is chiefly 

 resorted to in the case of plants which cannot easily be reproduced 

 from cuttings, and for such it is very advantageous. The plants 

 to be layered may be divided into two groups : (i) Those pos- 

 sessing woody shoots, such as trees and shrubs, in which cases it 

 is generally preferable to use well-ripened shoots ; and (2) 

 herbaceous plants having soft stems provided with leaves, in 

 layering which it is advisable to remove the leaves from the 

 portion of the stem to be layered. For hardy outdoor plants 

 layering may be successfully performed in the open during summer 

 months. For indoor layers no increase of heat is required. 



Reproduction by layering is also divided into several classes, 

 all answering the same purpose, but each particular principle 

 being applied more or less to a certain kind of plants. The 

 chief methods are bending or pegging the branch into the 

 ground, tongueing, ringing, piercing, and insertion of the growing 

 point, &c. 



Bending. — The simplest mode of layering is to bend into 

 prepared ground the selected branch. Only a few buds must be 

 retained close to the top, but all lower buds or eyes that would 

 be buried must be carefully removed. The underground, portion 

 is- fixed in such a manner as to prevent it from shifting, and the 

 extremity must be fixed to a stake to keep it in an upright 

 position. 



Ringing is another method which is very well illustrated in 

 Fig. 618, b. The branch is bent into the ground and well 

 secured by a peg; a kind of ring is taken out of the bark, 

 but in this case the outer and inner portion of the layers is 



