THE STEM i8i 



storage, only in much larger quantities, is also found in 

 other parts of the plant. It is deposited, for instance, 

 in the pith, in the medullary rays, in a word, in the 

 fundamental tissue of the stems. In the pith of the 

 sago-palm, starch is stored, in quantities which can be 

 measured by hundreds of pounds ; potato-tubers also 

 store starch, the beetroot an abundance of sugar, 

 cabbage-heads or turnip roots the most varied nutrient 

 substances ; lastly, in the fleshy leaves of the afore- 

 mentioned Agave, sugar is stored up during many years. 

 In fact, there is scarcely any vegetable organ which 

 may not become the receptacle and store-house of 

 nutrient substances. These stores are either used up 

 the next year after they are deposited, as is the case 

 with the beetroot or cabbage, where the stores are 

 spent on the development of the stem and flower organs 

 in the second year of the plant's existence ; or else they 

 are accumulated during many years, as is the case with 

 the sugar in the leaves of the Agave, which is eventually 

 spent in the formation of a huge branching inflorescence 

 bearing the flowers and fruit. In every case storage 

 is only a temporary, transitory destination of nutrient 

 substances : their final destination is reached only 

 when they are entirely used up in the formation of 

 new parts of the plant, of new organs, new cells, i.e. 

 when they contribute to its growth. Thus after having 

 studied the phenomena of nutrition, in the sense of 

 absorption, digestion, and translocation of food, we can 

 pass in our next chapter to the study of the phenomena 

 of growth. 



