220 



CIRCUMNUTATION OF STOLONS. CHAP. IV. 



of damp moss had emitted 2 stolons, 22 and 20 inches in length. 

 One of these was supported, so that a length of 4 inches pro- 

 jected in a straight and horizontal line, and the movement 

 of the apex was traced. The first dot was made at 9.10 A.M. ; 



Fig. 89. 



Cotyledon umbilicus: circumnutation of stolon, traced from 11.15 A.M. 

 Aug. 25th to 11 A.M. 27th. Plant illuminated from above. The 

 terminal internode was '25 inch in length, the penultimate 2 '25, aud 

 the third 3'0 inches in length. Apex of stolon stood at a distance of 

 5 * 75 inches from the vertical glass ; but it was not possible to ascertain 

 how much the tracing was magnified, as it was not known how great 

 a length of the internode circumnutated. 



the terminal portion soon began to bend downwards and con- 

 tinued to do so until noon. Therefore a straight line, very 

 nearly as long as the whole figure here given (Fig. 89), was first 

 traced on the glass ; but the upper part of this line has not been 

 copied in the diagram. The curvature occurred in the middle 



