434 MODIFIED CIRCUMNUTATION. CHAP. VIII. 



all pointing to the ground, was reversed, being still kept hori- 

 zontal, so that the pods now pointed directly upwards ; it was 

 then placed in a dark cupboard, but the pods still pointed up- 

 wards after four days and nights. The pot, in the same position, 

 was next brought back into the light, and after two days there 

 was some bending downwards of the peduncles, and on the fourth 

 day two of them pointed to the centre of the earth, as did the 

 others after an additional day or two. Another plant, in a pot 

 which had always stood upright, was left in the dark cupboard 

 for six days ; it bore 3 peduncles, and only one became within this 



Fig. 179. 



Cyclamen Pi-rsfritm: downward apheliotropic movement of a flower-peduncle, 

 .erctttly magnified (about 47 times ?), traced on a horizontal glass from 

 1 P.M. Feb. 18th to 8 A.M. 21st. 



time at all bowed downwards, and that doubtfully. The weight, 

 therefore, of the pods is not the cause of the bending down. 

 This pot was then brought back into the light, and after three 

 days the peduncles were considerably bowed downwards. We 

 are thus led to infer that the downward curvature is due to 

 apheliotropism ; though more trials ought to have been made. 



In order to observe the nature of this movement, a peduncle 

 bearing a large pod which had reached and rested on the 

 ground, was lifted a little up and secured to a stick. A filament 

 was fixed across the pod with a mark beneath, and its move- 



