SUGAR-CANE 405 



503. Structure of the stem. — The sugar-cane stem 

 is composed of juice and fiber. The outer part, commonly 

 called the rind, consists of a strong, tough fibrous tissue 

 which gives strength and firmness to the stem. Inclosed 

 by the rind are the white" pith-cells which contain the 

 saccharine juice. Numerous fine parallel fibers extend 

 lengthwise the stem through the pith-cells of the inter- 

 nodes and are closely woven together at the nodes. For 

 this reason the nodes are especially dense and fibrous and 

 contain very little juice. These fibrous strands extending 

 throughout the stem contain the vessels or passages 

 through which the water and dissolved plant-food fronx 

 the soil p,re brox;ght upward to the leaves, and also the 

 smaller vessels known as "sieve tubes" which convey the 

 digested sap from the leaves to the other parts of the plant: 



As the fiber is most compact at the nodes it follows that 

 those stems having numerous hodes close together are 

 lowest in juice. For this reason canes with long internodes 

 are generally desired, other things being equal. It fre- 

 quently happens, however, that the canes that are low 

 in fiber and therefore high in sugar are less resistant to 

 diseases and the ravages of stalk borers than the more 

 fibrous sorts. In some cases this susceptibility to disease 

 makes it necessary to replace the long-jointed, delicate 

 sorts with varieties having more fiber. Varieties with 

 large stems are generally viewed with more favor than 

 those with small stalks because of their greater strength, 

 and because they contain more available space for the 

 production of juice. 



504. Amount and distribution of juice. — The juice 

 often makes up as much as 90 per cent of the weight of the 

 stripped 'stems. The amount of juice varies with different 

 varieties and under different environmental conditions. 



