AUTONOMIC MOVEMENTS IN SUCCULENTS 



299 



Casual observations made it seem probable that the various 

 positions assumed by the joints were related to the degree of 

 turgidity of the tissues. Hence measurements were made on 

 plants in wet and in dry soil. In potted plants the soil water- 

 content could, of course, be controlled. The measurements on 

 plants growing in the open were made at various times of the 

 year when the interval between rains was known. 



The first set of observations was made on both potted plants 

 and on plants growing out of doors. The differences in posi- 



TABLE 1 



The relation of movements of joints of punt i a to the water-content of the soil. 



Plant No. 2 



Oct. 2 to 17 

 Oct. 17 to 22 



No water given between 

 the dates. Pot open. 



Watered every two days 

 after Oct. 17 



Plant No. 3 



May 27 to Aug 7 

 Aug. 7 to 11 



No water given between 



dates. Pot sealed. 

 Watered on Aug. 7 



Plants Nos. 7 and S 



Oct. 22 to Jan. 21 



Jan. 21 to Mar. 20 



No water given between 

 dates. Pots sealed. 



Watered frequently after 

 Jan. 21. 



Plants A and C 



