BY SUBDIVISION. 195 



The most favorable season for propagating by layers, 

 in these temperate latitudes, is the latter end of February 

 or the beginning of March. This season is called by 

 gardeners the first spring : it precedes the ascent of the 

 sap, arid enables the layers to collect the first drops of 

 cambium which are elaborated. In England and other 

 northern climates, where vegetation is less forward, the 

 end of March, which is called the second spring, is suffi- 

 ciently early for this purpose. The month of April, in 

 which the budding of the leaf takes place, is denomina- 

 ted the third spring. 



The safest way to ensure the success of layers is to 

 leave them a year without separating them from the pa- 

 rent stock, in order to give them the chance of striking 

 root during the ascent of the autumnal sap, if they have 

 failed to do so in the spring. 



Both succulent and aqueous plants are very difficult to 

 propagate by layers ; because the cambium, instead of 

 forming a protuberance to nourish the germs, runs out and 

 is lost. The operation is more likely to succeed on plants 

 of this description by strangulation than by incision. 



The propagation of plants by slips is very analogous 

 to that of layers ; indeed the only difference is, that the 

 branch you destine to become a new plant is separated 

 from the parent stem previous to the developement of 

 those organs which are necessary to insure it an inde- 

 pendent existence. 



Caroline. I am much better acquainted with this 

 species of propagation, I have raised so many geraniums 

 by slips. Nothing is more easy : you merely cut off a 

 young branch, and plant it in a pot of earth. But I am 

 completely ignorant how it lives : whether it absorbs 

 water before it strikes root, or whether it nourishes the 

 embryo roots by its own substance. 



Mrs. B. I believe no one can boast of having a per- 

 fect knowledge of the process ; but I am inclined to 

 think, that the cambium which descends in the slip, and 

 which was destined to nourish the lower part of the 



1068. In temperate latitudes what is the most favorable season for 

 propagation by layers'? 1069. What one in England 1 ? 1070. 

 What is called the third spring"? 1071. What is the most safe way 

 to secure the success of layers'? 1072. What is said of propagating 

 succulent and aqueous plants by layers'? 1073. What is the differ- 

 ence between propagating plants by slips and by layers'? 



