CHAP. IV 



CIRCUMNUTATION OF STEMS 



209 



day (8th) it zigzagged greatly, and on the 9th moved irregu- 

 larly round and round a small circular space. By 3 P.M. on 

 the 9th the figure had become so complicated that no more dots 

 could be made ; but the shoot continued during the evening of 

 the 9th, the whole of the 10th, and the morning of the llth to 



Fig. 79. 



Azalea Indica : circum nutation 

 of stem, illuminated from 

 above, traced on horizontal 

 glass, from 9.30 A.M. March 

 9th to 12.10 P.M. on the 10th. 

 But on the morning of the 

 10th only four dots were 

 made between 8.30 A.M. 

 and 12.10 P.M., both hours 

 included, so that the circum- 

 nutation is not fairly repre- 

 sented in this part of the 

 diagram. Movement of the 

 bead here magnified about 

 30 times. 



Fig. 80. 



Plumbago Capensis : circumnu- 

 tation of tip of a lateral 

 branch, traced on horizontal 

 glass, from 7.20 P.M. on 

 March 7th to 3 P.M. on the 

 9th. Movement of bead 

 magnified 13 times. Plant 

 feebly illuminated from 

 above. 



circumnutate over the same small space, which was only about 

 the i^th of an inch ('97 mm.) in diameter. Although this 

 branch circumnutated to a very small extent, yet it changed its 

 course frequently. The movements ought to have been more 

 magnified. 



(15.) Aloysia citriodora (Terbenacese, Fam. 173). The follow- 

 ing figure (Fig. 81) gives the movements of a shoot during 



P 



