Spalding : Mechanical adjustment of suaharo 



67 



{fis^^^ 



observation 



to the 



one-half an inch in ten days after the ra 

 p, curve 7). 



To summarize briefly, the foregoing 

 following results : 



1. Changes in the circumference of the stem of the suaharo 

 are accomplished by a bellows-like action of the ribs, which draw 

 closer together as the circumference decreases/ and move farther 

 apart as it increases. 



2. These movements are directly correlated with increase and 

 decrease in the water supplied to the plant, and with correspond- 

 ing changes in the quantity of water held by its storage tissue. 



Jan. 



February 



March 



April 



en e* « toe 





** w 



« 



o 

 n e* 



Figure 9. Six curves from the furrows facing nearest south on the same plants. 

 The curves marked 4 in this figure and the preceding show the variation caused by an 

 overflow of the water tank on March 18, Rain, February 6 (0.54 in. ). 



3. Variations in the circumference of the stem, due to changes 

 of water-content, are not the same at all heights, but are least pro- 

 nounced at the base and top, 



4. In their expansion and contraction, the furrows on the north 

 and south sides vary at different rates, which correspond with a 

 difference in the configuration of the two sides. 



