G8 Spalding : Mechanical adjustment of suaharo 



r 



5. Changes in the circumference 0/ the stem effected by the 

 mechanism described, while permitting free expansion and con- 

 traction of the water-storing tissue, leave the efficiency of the me- 

 chanical system unimpaired through all the vicissitudes to which 

 the plant is subjected, and which it resists with a remarkable decree 

 of success. 



Desert Botanical Laboratory, 

 Tucson, Arizona. 



Description of plates 3 antl 4 



Plate 3. Suaharo number i. Plant about 12 Veet high, marked for observation 

 about half way between base and apex. 



Plate 4. Suaharo number 4. A double-stemmed plant about six feet high, sbow- 

 ing the very frequent enlargement of the stem nearlhe top. 



