424 



MODIFIED CIIiCUMNUTATION. CHAP. VIH 



similar to the previous one. In these two cases there could be 

 no doubt that the ordinary circumnutating movement of the 

 hypocotyl was modified and rendered heliotropic. 



Fig. 171. 



Apios tjrnreofens : heliotropic movement and circumnutation of the hypo- 

 cotyls of two seedlings towards a dim lateral light, traced on a horizontal 

 glass during the day. The broken lines show their return nocturnal 

 courses. Height of hypocotyl of A - 5, and of B '55 inch. Figure reduced 

 to one-half of original scale. 



_,_w derarea. The hypocotyl of the cabbage, when not 



disturbed by a lateral light, circumnutates in a complicated 



