56 



CIKCUMNUTATION OF SEEDLINGS. CHAP. L 



this was in parts straight and in parts decidedly zigzag, 



indicating circumnutation. 



On the following day the other secondary shoot was observed ; 



it was a little more advanced in age, for the upper part, instead 

 of depending vertically downwards, 

 stood at an angle of 45 above the 

 horizon. The tip of the shoot pro- 

 jected obliquely '4 of an inch above 

 the ground, but by the close of our 

 observations, which lasted 47 h., it 

 had grown, chiefly towards its base, 

 to a height of 85 of an inch. The 

 filament was fixed transversely to 

 the basal and almost upright half 

 of the shoot, close beneath the lowest 

 scale-like appendage. The circum- 

 nutating course pursued is shown 

 in the accompanying figure (Fig. 

 42). The actual distance traversed 

 from side to side was about '04 of 

 an inch. 



Pinus pinaster (Coniferae). A 

 young hypocotyl, with the tips 

 of the cotyledons still enclosed 

 within the seed-coats, was at first 



only *35 of an inch in height; but the upper part grew so 



rapidly that at the end of our observations it was 6 in height, 



\ 



Corylus avellana: circumnuta- 

 tion of a young shoot emitted 

 from the epicotyl, the apex 

 of which had been injured, 

 traced on a horizontal glass, 

 from 9 A.M. Feb. 2ud to 8 

 A.M. 4th. Movement ol 

 bead magnified about 27 

 times. 



Fig. 43. 



Pinm pinaster : circumnutation of hypocotyl, with filament fixed across its 

 summit, traced on horizontal glass, from 10 A.M. March 21st to 9 A.M. 

 23rd. Seedling kept in darkness. Movement of bead magnified about 

 35 times. 



