378 



MODIFIED OIECUMNUTATION. 



Chap. "V'll. 



fitiok, and tlie movements of two leayes were traced on a vertical 

 glass during 72 h. The plants were still kept in the dark, ex- 

 cepting that at each observation, which lasted 3 or 4 minutes, 



Fig. 158. 



T'SOp.m 



f»:BO''p.m. 



tu'^o'a.iiUS'^ 



jt:ao'a..>ti 



Mimosa pudica ; circumnutation and nyctitropic movement of a leaflet 

 (with pinna secured), traced on a vertical glass, from 8 A.M. Sept. 14tli 

 to 9 A.M. leth. 



they were illuminated by two candles. On the third day the 

 leaflets still exhibited a vestige of sensitiveness when forcibly 

 pressed, but in the evening they showed no signs of sleep. 

 Nevertheless, their petioles continued to circumnutate distinctly, 



