CHAPTER VI 



THE STEM 



IF we consider the plant exclusively from the point of 

 view of nutrition, we are entitled, as has already been 

 said, to see in it simply two strongly developed surfaces 

 adapted to the twofold medium in which the plant 

 lives. These are the root-surface and the leaf-surface : 

 the former, being adapted to the solid medium, the soil, 

 is developed specially in length, because the root must 

 come into contact with the greatest possible number of 

 particles of the soil ; the latter, being adapted to the 

 absorption of atmospheric particles and, especially, to 

 the absorption of the light that falls upon it, is developed 

 especially in one plane. Owing to such an arrangement, 

 under favourable conditions scarcely a particle of the 

 soil can escape the root, nor a single ray of sunshine be 

 lost to the plant. 



The substances absorbed by the root and the leaf 

 are totally different, but at the same time are equally 

 necessary to the plant. Evidently the existence of each 

 of these organs, the very existence indeed of the whole 

 plant, requires that there should be constant intercourse 

 between them. 



The organ joining the two surfaces, which bears 

 the leaves and serves as intermediary between them and 

 the root, is the stem. As an intermediary this stem is 

 not an organ so essentially necessary to the plant as the 

 root or the leaf, and it is therefore sometimes very 

 poorly developed ; but where, on the contrary, it is well 

 developed it plays the most prominent part in determin- 

 ing the general aspect of the plant, and, in fact, the 



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