CHAP. IV. CIKCUMNUTATION OF STEMS. 213 



filament, with a bead at the end, was fixed across the summit 

 of a young stem 10 inches in height, close beneath the crown of 

 elongated leaves. On March 8th, between 12.20 and 7.20 P.M., 

 the stem described an ellipse, open at one end. On the follow- 

 ing day a new tracing was begun (Fig. 84), which plainly shows 

 that the stem completed three irregular figures in the course of 

 35 h 15 m. 



Concluding Remarks on the Circumnuiation of Stems. 

 Any one who will inspect the diagrams now given, and 

 will bear in mind the widely separated position of the 

 plants described in the series, remembering that we 

 have good grounds for the belief that the hypocotyls 

 and epicotyls of all seedlings circumnutate, not 

 forgetting the number of plants distributed in the 

 most distinct families which climb by a similar move- 

 ment, will probably admit that the growing stems 

 of all plants, if carefully observed, would be found 

 to circumnutate to a greater or less extent. When 

 we treat of the sleep and other movements of plants, 

 many other cases of circumnutating stems will be 

 incidentally given. In looking at the diagrams, we 

 should remember that the stems were always growing, 

 so that in each case the circumnutating apex as it 

 rose will have described a spire of some kind. The 

 dots were made on the glasses generally at intervals 

 of an hour, or hour and a half, and were then joined 

 by straight lines. If they had been made at intervals 

 of 2 or 3 minutes, the lines would have been more 

 curvilinear, as in the case of the tracks left on the 

 smoked glass-plates by the tips of the circumnutating 

 radicles of seedling plants. The diagrams generally 

 approach in form to a succession of more or less 

 irregular ellipses or ovals, with their longer axes 

 directed to different points of the compass during the 

 same day or on succeeding days. The stems ttyere- 



