30 



CIECUMNUTATION OF SEEDLINGS. 



Chap. I 



abruptly, then made a small loop and then a larger zigzag 

 curve. During the night and till 11a.m. on the following 



Fig. 20. 



Vicia faba: circumnutation of a radicle, at first pointiiig rerti/ally up- 

 wards, kept in darkness, traced on a horizontal glass, during 14 hour.'. 

 MoTemcnt of bead of filament magnified 23 times, here reduced to 

 one-half of original scale. 



morning, the bead moved to a great distance in a nearly straight 

 line, in the direction indicated by the broken line in the figure. 

 This resulted from the tip bending quickly do-wnwards, as it 

 had now become much declined, and had thus gained a positiou 

 tiighly favourable for the action of geotropism. 



Fig. 21. 



0. 



D. 



£. 



fSeh faba : tracks left on inclined smoked glass-plates, by tips of radicles 

 in growing downwards. Plate C was inclined at 63°, plates A and D 

 at 71°, plate B at 75°, and plate E at a few degrees beneath the 

 horizon. 



