208 



CIECUMNUTATION OF STEMS. 



Chap, rv, 



they were found to be still circumnutating, but on a yet smaller 

 scale. 



(12.) Gazania ringens (Compositse, Fam. 122). — The circum- 

 nutation of the stem of a young plant, 7 inches in height, as 

 measured to the tip of the highest leaf, was traced during 

 33 h., and is shown in the accompanying figure (Fig. 78). Two 



Fig. 78. 



ei/i-m.ss^i 



91.32" 



Gazania rinjens: cii'cutrinutation of stem traced from 9 A.M. March 21st 

 to 6 P.M. OQ 22nd ; plant kept in darkness. Movement of bead at the 

 close of the observations magnified 34 times, here reduced to half the 

 original scale. 



main lines may be observed running at nearly right angles to 

 two pther main lines; but these are interrupted by small 

 loops. 



(13.) Azalea Indica (Ericineae, Fam. 128). — A bush 21 inches 

 in height was selected for observation, and the circumnutation 

 of its leading shoot was traced during 26 h. 40 m., as shown 

 in the following iigure (Fig. 79). 



(14.) Plumbago Capennis (Plumbaginese, Fam. 134). — A small 

 lateral branch which projected from a tall freely growing bush, 

 at an angle of 35° above the horizon, was selected for obser- 

 vation. For the first 11 h. it moved to a considerable distance 

 in a nearly straight line to one side, owing probably to its 

 having been previously deflected by the light whilst standing in 

 the greenhouse. At 7.20 p.m. on March 7th a fresh tracing was 

 begun and continued for the next 43 h. 40 m. (see Fig. 80). 

 During the first 2 h. it followed nearly the same direction as 

 before, and then changed it a little; during the night it 

 moved at nearly right angles to its previous course. Next 



