488 



SOUTHERN FIELD CROPS 



At intervals among these pith cells may be found strands of 

 tougher tissue running parallel to the length of the stalk (Fig. 

 208). These tough, strong strands are the bundles of fibrous 

 tissue that serve for the circulation of liquids within the plant. 

 Each bundle (Fig. 209) contains (1) several vessels, that is, organs 



FIG. 209. CROSS SECTION THROUGH A BUNDLE FROM THE STEM OF 

 SUGAR-CANE. 



V, vessels for upward current ; S, sieve tubes for the descending sap ; 

 P, pith cells containing sugar. Greatly enlarged. 



for the carrying of water and dissolved plant-food from the soil 

 upward to the leaves ; (2) a number of smaller carriers, called 

 sieve tubes, through which the digested sap is returned from the 

 leaves to all the other parts of the plant. 



