OSMOTIC PRESSURES AND ELECTRICAL CONDUCTIVITIES 161 



seen that the pressures exerted by the electrolytes are 

 small compared with those due to the carbohydrates and 

 other non-electrolytes. In most varieties of roots and 

 rhizomes, however, the two classes of bodies share in pro- 

 ducing the pressures fairly evenly, though in some the 

 influence of the electrolytes is most marked in Equisetum, 

 for example. The leaves of Allium, Beta, Brassica, and 

 Helianthus, were not examined, but by analogy it is likely 

 that they have even higher pressures than the underground 

 organs. 



TABLE XL. 

 OSMOTIC PRESSURE OF SUBTERRANEAN ORGANS. 



Roots functioning mainly as water-absorbing organs do 

 not usually contain sufficient solutes to cause high pres- 



11 



