CHAPTER X 



OSMOTIC PRESSURE IN RELATION TO PLANT 

 DISTRIBUTION, MORPHOLOGY, AND CELL DIVISION 



SECTION I. DISTRIBUTION. 



DESERT PLANTS. 



IN order that a plant may be able to absorb water from its 

 surroundings it is necessary for its total forces of capillarity, 

 imbibition, and osmotic attraction, to exceed those of its 

 medium. Now, in plants growing in arid regions very 

 high osmotic pressures are met with, as has been shown by 

 Fitting's (1911) plasmolytic determinations, some of which 

 are quoted in Table XLII. 



TABLE XLII. 

 FLOBA OF ROCKY DESERT IN SAHARA. 



In the first column it may be noticed that the percen- 

 tages reach the total of 119. On recalculating them from 

 Fitting's data, the values 21, 39, 26, and 11, were obtained. 

 Thus, allowing for the inclusion of some border-line results 



171 



