214 VEGETABLE ORGANOGRAPHY. 



the contrary, the wounded or cut root is found near the 

 surface of the soil, instead of roots it is a young stem 

 which is developed. It is for this reason, that on 

 wounding roots extended horizontally, we cause trees 

 to produce suckers. 



What we have said with regard to roots equally 

 applies to steins. If a ligature or incision be made on 

 the bark of a tree, a rim is formed above it ; if this be 

 surrounded with earth and wet moss, it shoots out 

 roots : this is the rationale of the manner by which 

 cultivators multiply plants by layers. If a branch be 

 cut off and placed in the ground, the part which is 

 buried produces roots : this is what takes place in the 

 multiplication of plants by cuttings. Lastly, if after 

 having made an incision or ligature on the bark of a 

 tree, the rim which is formed be allowed to be exposed 

 to the air, it frequently develops new branches. 



AU that I have set forth with regard to those cases 

 where the plants have been submitted to the influence 

 of man, is presented in certain species as a necessary 

 consequence of their organization. Thus, when a plant, 

 instead of protruding its roots vertically into the earth, 

 has them horizontally under the surface of the soil, 

 each time these roots are found uncovered by the effect 

 of the inequalities of the ground, they will be likely to 

 produce new stems. This is what happens in roots said 

 to be creeping ; for example, those oi Ranunculus repens. 

 In the same manner, prostrate stems having one of their 

 sides constantly exposed to the moisture of the soil, are 

 disposed to shoot out roots from this side, if there be 

 ever so little a stagnation of their juices. This is what 

 takes place in the creeping stems of Mesemhryanthenmm 

 linguiforme , M. reptans, &c. 



The nodes or articulations of stems are points where 

 nature has prepared beforehand a rest — a stagnation in 



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