CHAP. IV. CIRCUMNUTATION OF STOLONS. 



215 



morning after an interval of 20 h. the apex stood a little higher 

 lhan it did at first, and this shows that the stolon had not been 



Fig. 85. 



10pm.S 



J04,5'q.m 

 18 



: circumnutation of stolon, kept in darkness, traced on vertical 

 glass, from 10.45 A.M. May 18th to 7.45 A.M. on 19th. 



acted on within this time by geotropism;* nor had its own 

 weight caused it to bend downwards. 



On the following morning (19th) the glass filament was 

 detached and refixed close behind the bud, as it appeared pos- 

 sible that the circumnutation of the terminal bud and of the 

 adjoining part of the stolon might be different. The movement 

 was now traced during two consecutive days (Fig. 86). During 

 the first day the filament travelled in the course of 14 h. 30 m. 

 five times up and four times down, besides some lateral move- 

 ment. On the 20th the course was even more complicated, and 

 can hardly be followed in the figure ; but the filament moved in 

 16 h. at least five times up and five times down, with very little 



* Dr. A. B. Frank states (' Die 

 Naturliche wagerechte Richtung 

 von Pflanzentheilen,' 1S70, p. 20) 

 that the stolons of this plant are 



acted on by geotropism, but only 

 after a considerable interval of 

 time. 



