INDUCED RHYTHM IN TRANSPIRATION. 



6 9 



8p.m. 10 12 2a.m. 4 6 8 10 12 2p.m. 4 6 



Fig. 24. — Curves for experiments 65 and 66. Fouquieria splendens, 



In all the above eight cases the rate commences to increase shortly after 

 midnight and rises to an early maximum, in five cases at 6 a. m., and in one 

 (60) at 5 a. m. In the controls a normal behavior is shown, the maximum 

 being reached at 12 day and 3 p. m. The drop in 66 between 11 a. m. and 

 12 day was due to a 15-minute exposure to darkness. 



Experiments 73, 74. — July 21, 1904. Ocotillo. Burette potometer; pieces placed in dark 



room at io h 30 m p. m., reading commenced at 6 h 30 m a. m., a maximum was developed at 



7 h 30 m a. m. (See fig. 18, of experiment 74 only.) 

 Experiments 80, 81, and 82. — Aug. 10-11, 1904 (fig. 25). Placed in dark room at 9 p. m.; 



placed in light at 10 a. m., after 15 hours of total darkness; temperatures given during 



these hours are those of dark room. 

 Experiment 83, fig. 26, differed only in being placed in the light for 5 minutes, at 9^30™ 



a. m., Aug. 11. 



2p.m. 4 6 8 10 12 2a.m 



Fig. 25. — Curves for experiments 80, 81, and 82. 



4 6 8 



Fouquieria splendens. 



