302 PROPAGATION BY LAYERS. 



layering brittle-branched plants by simply slitting the shoot at 

 the bend, and inserting a stone at that place (Gardeners' 

 Magazine, ix. 303) : and Mr Knight found that, in cases of 

 difficult rooting, the process is facilitated by ringing the shoot 

 just below the tongue, about midsummer, when the leaves 

 upon the layers had acquired their full growth (Hort. Trans., 

 i. 256); by which means he prevented the return of sap 

 further downwards than the point intended to root. 



It will sometimes happen that the branch of a plant cannot 

 be conveniently bent downwards into the earth ; in such cases, 

 the earth may be elevated to the branch by various contri- 

 vances, as is commonly practised by the Chinese. In this 

 no other care is necessary than that required for layers, except 

 to keep the earth surrounding the branch steadily moist. 



Suckers are branches naturally thrown up by a plant from 

 its base, when the onward current of growth of the stem is 

 stopped. Where this occurs the onward growth of a plant is 

 arrested, the sap is driven to find new outlets, and adventitious 

 buds (see p. 44) are very likely to be developed ; the well-known 

 effect of cutting down a tree is an exemplification of this. 

 Such branches, if they proceed from under ground, sometimes 

 form roots at their base, in which case they are employed as a 

 means of propagation ; in the instance of the Pine-apple, they 

 are made use of for the same purpose, although they do not 

 emit roots till they are separated from the parent. Gardeners 

 usually satisfy themselves with taking from their Pine-apple 

 plants such suckers as are produced in consequence of the 

 stoppage of onward growth by the formation of the fruit : but 

 these 'are few in number, and not at all what the plant is capable 

 of yielding. Instead of throwing away the " stump " of the Pine- 

 apple, it should be placed in a damp pit, and exposed to a 

 bottom heat of 90° or thereabouts, when every one of the latent 

 eyes will spring forth, and a crop of young plants be the result. 

 Mr. Alexander Forsyth, an experienced writer upon these sub- 

 jects, pointed this out some years since in the Gardeners' Maga- 

 zine (xii. 594) ; and there can be no doubt that his observations 

 upon the folly of throwing away "stumps" are perfectly correct 

 both in theory and practice. 



